Sigma Nutrition Radio

When discussing cardiovascular health, few topics stir as much debate as cholesterol, particularly in relation to low-carb and ketogenic diets. Recently, there’s been significant attention given to a proposed model that suggests high LDL cholesterol may not pose the same cardiovascular risk in certain individuals, specifically those labeled as “lean mass hyper-responders.” This raises important questions: Is it possible that high cholesterol might not be dangerous for everyone? Or are we witnessing a dangerous misinterpretation of the science?

In this episode, we break down the ideas behind the “lipid energy model” and explore how it has been framed in the context of low-carbohydrate and ketogenic diets. While proponents claim this model sheds light on how some people can have elevated LDL without increasing heart disease risk, critics warn that miscommunication and oversimplification of these ideas are leading many down a dangerous path. With real-world health decisions hanging in the balance, it’s crucial to carefully examine what the science truly says about cholesterol, inflammation, and heart disease.

Join us as we dive into the evidence with Dr. Gary McGowan. We’ll dissect what the current research supports, what remains speculative, and how social media has amplified both the promising and problematic aspects of this model. If you’ve ever wondered about the impact of high cholesterol on heart disease risk in the context of ketogenic or low-carb diets, this episode is essential listening.

• 02:27 What are the “Lean Mass Hyper Responder” phenotype and the “Lipid Energy Model”
• 27:29 Looking at recent publications and the “KETO Trial”
• 47:06 Public communication and misinterpretation
• 51:18 Clinical implications of diet-induced dyslipidemia
• 55:14 Responsibility in scientific communication
• 57:30 Real-world examples of poor communication or misinterpretation
• 01:13:27 Ethical concerns with the promotion of the model
• 01:25:59 Final thoughts

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• Find Dr. McGowan at:
  • Triage Method
  • Instagram: @drgarymcgowan
• Papers discussed in this episode:
  • Norwitz et al., 2022 – The Lipid Energy Model: Reimagining Lipoprotein Function in the Context of Carbohydrate-Restricted Diets
  • Norwitz et al., 2021 – Elevated LDL Cholesterol with a Carbohydrate-Restricted Diet: Evidence for a “Lean Mass Hyper-Responder” Phenotype
  • KETO Trial: Budoff et al., 2024 – Carbohydrate Restriction-Induced Elevations in LDL-Cholesterol and Atherosclerosis

Fasting has gained immense popularity as a dietary approach, but what does the scientific evidence say about its health benefits?

Studies have explored how fasting might influence metabolic markers, energy expenditure, and even aging. However, while fasting shows promise in some animal models, translating these effects to humans is less clear.

A key part of the debate centers on whether fasting offers unique health advantages or whether its benefits stem primarily from reduced calorie intake. Time-restricted eating and intermittent fasting protocols show promise in regulating appetite and reducing energy intake, potentially leading to weight loss. But, when calories are controlled, does fasting still improve health independently?

This episode explores the evidence to determine if fasting confers metabolic advantages over non-fasting diets. In addition, we’ll take a look at its impact on behavioral patterns and ask if that could play a pivotal role in promoting better health outcomes.

To listen to this episode in full, subscribe to Sigma Nutrition Premium.

Timestamps:

• [00:54] Defining fasting
• [03:44] Historical context and early research
• [08:01] Mechanisms and claims of fasting
• [18:15] Types of fasting protocols
• [22:18] Time-restricted eating and chronobiology
• [28:29] Energy expenditure and behavioral changes
• [36:53] Fasting vs. weight loss: independent benefits
• [41:47] Health markers and weight loss outcomes
• [43:37] Muscle mass concerns during fasting
• [47:31] Animal models vs. human studies
• [51:29] InterFAST study insights
• [01:00:37] Behavioral vs. metabolic changes
• [01:11:25] So what do we know?

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• Go to the page for this episode

Body image and self-worth are deeply intertwined concepts that influence how we see ourselves and interact with the world. Many people believe that changing their physique is the key to improving their body image, but is it really that simple? This connection between appearance and self-esteem raises important questions about how we define confidence and whether our sense of worth should be tied to how we look.

Our relationship with food plays a crucial role in how we view ourselves. While some see food as fuel, others attach much more significance to their eating habits, often linking dietary choices to discipline, success, or failure. But what happens when these beliefs become too rigid? Understanding how our perceptions of food and body image are shaped is essential for navigating the balance between health, happiness, and personal fulfillment.

Physique change, often seen as a positive goal, can bring about unexpected psychological impacts. Pursuing a leaner or more muscular body might boost temporary feelings of confidence, but could it also reinforce negative patterns of thought?

In an episode co-hosted with Dr. Eric Trexler, Danny talks with Dr. Gabrielle Fundaro in order to tackle some of these concepts and questions.

Timestamps:

• [04:54] Start of conversation
• [06:40] Defining body image and self esteem
• [12:26] Relationship with food and weight controllability beliefs
• [20:38] Impact of body composition on body image
• [27:40] Challenges in changing body image perceptions
• [34:43] Influence of coaches on client body image
• [41:57] Screening for disordered eating
• [51:50] Ethical responsibilities of fitness professionals
• [54:53] Improving body image without physique change
• [61:02] Key ideas segment (premium-only)

Links:

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• Get more of Dr. Trexler’s research analysis with the MASS Research Review
• Related previous episodes: See episodes 484 and 367

Some suggest that, since individual lifts or short-duration efforts don’t rely heavily on glycogen, carb intake might not be critical for strength athletes. If glycogen depletion isn’t a pressing issue, could athletes thrive on lower-carb diets without sacrificing performance? Or could there be overlooked benefits to having greater carbohydrate availablily in those sessions?

• In strength sports and resistance training, do carbohydrates play an important role or not?
• Are carbohydrates really necessary for resistance training?
• How does training volume, intensity and goals impact the carbohydrate requirement?

In this episode, Dr. Cliff Harvey and Dr. Eric Helms offer their perspectives on this interesting and practically important issue.

Timestamps:

• [00:03:40] Do carbohydrates have a role in resistance training?
• [00:12:23] Do individuals respond differently?
• [00:18:25] Recent research insights
• [00:35:08] Carbohydrate “sensing” and performance
• [00:47:17] How to think about carbohydrate needs
• [00:54:06] Changing views on nutrient timing
• [01:06:37] Ketogenic diets and muscle gain
• [01:22:02] Dietary patterns and health – Are macronutrients that important?
• [01:31:42] Key ideas segment (Premium-only)

Links:

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• Sports Nutrition Association
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• SigmaNutrition.com

Omega-3 fatty acids are often viewed as beneficial or, at worst, neutral supplements when it comes to supporting cardiovascular health, lowering triglycerides, and offering anti-inflammatory effects. Much of the focus in recent years has centered on understanding how significant these benefits are, particularly for heart health, with many studies highlighting the potential for omega-3s to play a positive role in reducing cardiovascular risk. However, an emerging concern has complicated the conversation around omega-3 supplementation.

Several large trials, including the REDUCE-IT and STRENGTH trials, have suggested that omega-3 supplementation might be linked to an increased risk of atrial fibrillation (AF), a common cardiac arrhythmia characterized by an irregular and often rapid heart rate. These findings have sparked debate over whether omega-3s could contribute to this potentially serious heart condition, leaving clinicians and health-conscious individuals uncertain about the safety of these supplements.

However, not all the research supports this elevated risk. This discrepancy raises important questions about how we interpret the data from various studies, the design of those trials, and whether other factors might be influencing these results.

Understanding this issue in depth is crucial for making informed decisions about omega-3 supplementation and its potential risks and benefits. In this episode we walk through the studies and the key points to consider.

Timestamps:

• 00:30 Updates on Alan’s upcoming study
• 05:06 Atrial Fibrillation and Omega-3
• 14:52 RCTs and AFib: Key Studies
• 29:14 Meta-Analyses and Dose-Response
• 46:46 Practical Implications and Recommendations
• 53:53 Key Ideas Segment (Premium-only)

Links:

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• Go to episode page

This is an “ask me anything” (AMA) episode with Dr. Stephan Guyenet, an expert in obesity neuroscience and eating behavior. This episode was originally published on Sigma Nutrition Premium. If you’re interested in subscribing to Sigma Nutrition Premium, then check all the details here.

1. [04.27] If we surgically remove adipose tissue, do leptin levels suddenly drop? How would this impact hunger over time?
2. [06.56] How does chronic energy restriction (or following a crash diet) affect long-term appetite regulation?
3. [13.21] How do anorexia and pronounced obesity defy the rules of metabolic compensation?
4. [24.12] Why do some SDRIs (serotonin–dopamine reuptake inhibitors) reduce hunger/appetite?
5. [28.02] Can an algorithm really decipher someone’s “ideal weight?
6. [33.08] Could the “brain microbiome” impact appetite regulation and/or obesity?
7. [35.34] In our current environment, are the only efficacious interventions drugs and bariatric surgery?
8. [46.01] What should we make of claims by Gary Taubes about insulinogenic foods?
9. [52.37] Is there a maximum duration someone should spend in fat loss (or weight gain) phases?
10. [53.43] Why do some people struggle to gain weight?

Links:

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• View our recommended resources

1. [02:28] Caffeine metabolism and individual variation.
2. [14:47] High-sodium electrolyte supplements & recreational trainees.
3. [32:55] Is a “too low” BMI a problem?
4. [41:38] Are claims about vegan diets being nutritionally insufficient overblown?
5. [51:33] Familial hypercholesterolemia & further lipid-lowering
6. [58:05] Menopause, resistenace training and progressive overload
7. [01:11:56] Does body weight matter if someone has healthy behaviours?

This episode is one of our Premium-exclusive AMA (ask me anything) episodes, where we answer questions submitted by Premium subscribers. To listen to the full episode, you’ll need to be a Premium subscriber and access the episode on the private Premium feed.

Otherwise, you can hear the first question on the public feed of the podcast.

Links:

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In the world of combat sports, optimizing performance extends beyond physical training and nutrition—sleep plays a critical role. Maladaptive sleep behaviors, such as inconsistent sleep schedules and inadequate sleep duration, can significantly impair an athlete’s performance by reducing cognitive function, reaction time, and recovery ability. Understanding these impacts is crucial for athletes and coaches seeking to enhance performance through more effective sleep strategies.

One of the key challenges combat sports athletes face is managing the effects of shift work and irregular event timings, which often conflict with typical training schedules. What are some strategies to mitigate these challenges, such as adjusting sleep schedules in advance? And what are the implications of jet lag for athletes traveling to major competitions?

While technology offers valuable tools for tracking sleep, there are potential drawbacks, including reliance on inaccurate data or the psychological effects of constant monitoring. By educating athletes and coaches on best practices for sleep, they can make informed adjustments to training regimens, ultimately enhancing overall performance.

In this episode, sleep scientist Dr. Ian Dunican discusses his work related to understanding and improving sleep behaviors in combat sports athletes.

Timestamps:

• 01:43 Introduction to the Episode
• 04:38 Discussion on Recent Research Paper
• 09:52 Sleep Behaviors in Athletes
• 13:11 Questionnaire and Study Findings
• 20:38 Common Sleep Disorders in Athletes
• 33:23 Impact of Training Schedules on Sleep
• 34:25 Practical Tips for Better Sleep
• 41:17 Phases of Training and Their Importance
• 42:31 Understanding Chronotypes and Sleep Habits
• 45:19 Wearable Devices and Sleep Tracking
• 53:05 Practical Advice for Coaches and Athletes
• 59:03 Travel, Jet Lag, and Sleep for Athletes

Links:

• Enroll in the next cohort of our Applied Nutrition Literacy course
• Go to episode page (with links to studies in this episode)
• Dr. Dunican's course (20% off with code MELIUS20)
• Learn more about Sigma Nutrition
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To many, meta-analyses are seen as a research tool that is often regarded as the pinnacle of evidence in nutrition science. But is this accurate? What exactly makes a meta-analysis reliable or flawed? How can we distinguish between a well-conducted study and one that might mislead even the most well-intentioned reader?

In this episode, through three concrete examples, we explore the fundamental principles of meta-analyses, focusing on key aspects such as study selection, heterogeneity, and effect sizes. We discuss how these elements can significantly impact the conclusions drawn from a meta-analysis and what you should look out for when interpreting their results.

Whether you’re a nutrition professional, a researcher, or simply someone interested in the science behind dietary guidelines, this discussion will help you navigate the often murky waters of meta-analytic research.

Timestamps:

• 05:14 Understanding Meta-Analyses
• 12:11 Example 1: Dairy Consumption and Health
• 39:06 Example 2: Meta-Analysis on Carbohydrate Intake
• 54:59 Example 3: Meta-Analysis on Intermittent Fasting
• 01:02:44 Challenges in Meta-Analysis of Intermittent Fasting
• 01:13:56 Key Ideas Segment (Premium-only)

Links:

• Enroll in the next cohort of our Applied Nutrition Literacy course
• Meta-analyses discussed in the episode:
  • Example 1: Dairy Consumption and Health
  • Example 2: Meta-Analysis on Carbohydrate Intake
  • Example 3: Meta-Analysis on Intermittent Fasting
• Subscribe to Sigma Nutrition Premium

The debate between animal-based and plant-based meat alternatives (PBMAs) has garnered significant attention, especially concerning their impact on cardiovascular health. As PBMAs become increasingly popular, questions about their nutritional profiles and long-term health implications have emerged. Are these alternatives genuinely healthier than traditional meat, or do their highly processed nature and high sodium content undermine potential benefits? This discussion is crucial as dietary choices increasingly influence public health policies and consumer behaviors.

Dr. Matthew Nagra’s recent review in the Canadian Journal of Cardiology sheds light on these issues by analyzing the nutritional differences between PBMAs and meat. The review highlights the potential cardiovascular benefits of PBMAs, such as lower levels of saturated fat and cholesterol, alongside higher fiber content. However, the review also points out the significant variability in PBMAs’ nutritional content, raising questions about standardization and consumer guidance. Understanding these differences is key to making informed dietary decisions and shaping future food industry practices.

With growing consumer interest and public health implications, several pertinent questions arise: How do different PBMAs compare in their nutritional impact? What role does food processing play in their health outcomes? How can consumers make the best choices given the variability in PBMAs? In our discussion, Dr. Nagra will cover all these details, providing a comprehensive look at the current state of PBMAs and their role in a healthy diet.

Timestamps:

• 01:59 Introducing Dr. Matthew Nagra
• 10:48 Nutritional Profiles of Plant-Based Meat Alternatives
• 14:39 Cardiovascular Risk Factors and Review Findings
• 21:17 Public Perception and Criticisms
• 25:10 Practical Advice for Choosing Plant-Based Meat Alternatives
• 34:29 Future Research Directions
• 43:51 Key Ideas Segment (Premium-only)
•  

Links:

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• Go to episode page
• Receive our free weekly email: the Sigma Synopsis
• Enroll in the next cohort of our Applied Nutrition Literacy course

In the ongoing exploration of weight loss strategies, the timing of food intake has emerged as a fascinating area of study. While traditional advice often focuses on what we eat, growing evidence suggests that when we eat could also play a crucial role in weight management. This concept, known as chrononutrition, examines how our body’s internal clock influences the metabolic processes associated with food intake. Could adjusting meal times offer a new pathway to effective weight loss?

Recent research has delved into various hypotheses, including the energetic hypothesis, which proposes that meal timing can impact energy expenditure and intake. Studies have shown that consuming more calories earlier in the day could potentially enhance weight loss, independent of total daily calorie intake. This intriguing possibility has led scientists to investigate the mechanisms behind these effects, such as the thermic effect of feeding and diurnal variations in metabolism. Understanding these mechanisms could transform our approach to dietary planning and obesity management.

Dr. Alan Flanagan will be covering all the details in this episode, where he explores the latest evidence on meal timing and its impact on weight loss. He will dissect key studies, challenge prevailing assumptions, and provide a comprehensive analysis of the energetic hypothesis. Join us as we navigate the complexities of chrononutrition and uncover whether altering the timing of our meals can truly make a difference in our weight loss journeys.

This episode is a Premium-exclusive episode. Subscribe to Sigma Nutrition Premium to listen to the full episode.

Links:

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• Go to Sigma Nutrition Website

The impact of omega-3 fatty acids on chronic disease risk has been a topic of considerable interest and research. The VITAL trial, which assessed the effects of vitamin D and omega-3 supplements on various health outcomes, including cardiovascular disease and cancer, provided insightful findings. Additionally, numerous other supplement trials have examined different dosages and formulations of omega-3s, yielding mixed results. Some trials have highlighted significant benefits, while others have shown minimal impact, leading to ongoing debates in the scientific community.

Reconciling this evidence base requires a nuanced understanding of the study populations, dosages, and specific health outcomes investigated. The variability in results can often be attributed to differences in trial design, such as whether the focus was on primary or secondary prevention, the baseline dietary intake of participants, and the specific types of omega-3 supplements used. Understanding these nuances is crucial for making informed recommendations about omega-3 supplementation for chronic disease prevention.

In this episode, Professor JoAnn Manson will delve into the complexities of omega-3 research, discussing the VITAL trial in detail, comparing it with other significant studies, and providing insights into how to interpret and reconcile the diverse findings in the context of chronic disease risk.

Timestamps:

• 03:21 The VITAL Trial Explained
• 05:39 Biological Mechanisms and Observational Studies
• 07:25 Primary vs. Secondary Prevention
• 10:47 Key Findings from the VITAL Trial
• 13:39 Subgroup Analyses and Future Research
• 19:58 Dosage Considerations and Risks
• 23:47 Impact of Omega-3 on Chronic Diseases
• 32:18 Nuances in Omega-3 Research
• 44:27 Future Research Directions
• 48:54 Key Ideas Segment (Premium-only)

Links:

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• Go to episode page
• Receive our free weekly email: the Sigma Synopsis
• Enroll in the next cohort of our Applied Nutrition Literacy course

In the realm of nutrition science, few topics have sparked as much debate and evolution in understanding as the impact of dietary fat on cardiovascular health.

Dr. Alice Lichtenstein, a renowned expert in nutrition and cardiovascular disease, brings clarity to this complex field. Her extensive research at several prestigious institutions has been pivotal in shaping contemporary dietary guidelines.

Dr. Lichtenstein delves into the journey from early observational studies that linked high-cholesterol diets to cardiovascular risk to more nuanced insights emphasizing the types of fats consumed. The discussion highlights the critical shift from merely reducing total fat intake to replacing saturated fats with unsaturated fats, reflecting the latest evidence-based recommendations.

Furthermore, the conversation addresses the variability in individual responses to dietary changes and the ongoing debate over the most accurate biomarkers for assessing cardiovascular risk. Dr. Lichtenstein also tackles the pervasive issue of nutrition misinformation and underscores the necessity of robust, evidence-based public health guidelines.

This episode offers a comprehensive exploration of whole dietary patterns, the importance of examining food choices in context, and the role of public health policy in fostering healthier eating environments. Join us to gain a deeper understanding of how dietary fat influences health and the critical considerations for future nutrition research and recommendations.

Timestamps:

• 03:15 Dr. Lichtenstein’s Academic Background
• 05:47 Evolution of Dietary Fat Research
• 14:47 Understanding Cholesterol and Lipoproteins
• 23:47 Dietary Patterns and Public Health
• 29:51 Seed Oils & Nutrition Misinformation
• 34:06 Future Directions in Nutrition Research
• 47:11 Key Ideas Segment (Premium-only)

Links:

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• Go to episode page
• Receive our free weekly email: the Sigma Synopsis
• Enroll in the next cohort of our Applied Nutrition Literacy course

• 01:32 Understanding Correlation and Causation
• 03:54 Historical Perspectives on Causality
• 06:33 Causal Models in Health Sciences
• 14:53 Probabilistic vs. Deterministic Causation
• 30:52 Standards of Proof in Public Health
• 36:44 Applying Causal Models in Nutrition Science
• 58:54 Key Ideas Segment (Premium-only)

• Enroll in the next cohort of our Applied Nutrition Literacy course
• Go to episode page
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• Receive our free weekly email: the Sigma Synopsis
• Related episode: 343 – Understanding Causality in Nutrition Science

Regression to the Mean (RTM) is a statistical phenomenon where extreme values on one measurement tend to move closer to the average on subsequent measurements due to natural variability. In this Premium-exclulsive episode, Danny gives an explanation of this concept with some examples in nutrition research.

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• Go to episode page

• Subscribe to Sigma Nutrition PREMIUM
• Scott Young’s Website 
• SigmaNutrition.com
• Receive our free weekly email: the Sigma Synopsis
• Related Episode: #188: Barbara Oakley, PhD – How to Learn, Study & Get Better With Science

• 02:13 Introduction to Topic
• 04:41 Conversation with Scott Young Begins
• 06:56 Insights on Learning and Cognitive Science
• 12:42 Effective Learning Strategies
• 20:27 Overcoming Mental Barriers
• 31:14 Effective Teaching Strategies
• 35:14 The Importance of Feedback in Learning
• 38:52 Optimizing Your Learning Environment
• 44:29 Translating Complex Information for a General Audience
• 52:32 Key Ideas (Premium-Only)

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In episode 529 of Sigma Nutrition Radio, we discuss all things related to cholesterol, atherosclerosis, heart disease, and dietary fat. The discussion extensively covers the impact of LDL cholesterol and ApoB on atherosclerotic plaque progression, cardiovascular events, and the benefits of early LDL lowering interventions, particularly through the use of PCSK9 inhibitors alongside statins.

We address misconceptions prevalent in the low-carb and carnivore communities, dissect claims regarding saturated fats, and elucidate why atherosclerosis predominantly affects arteries and not veins. The episode sheds light on the nuanced mechanisms of cholesterol metabolism, the significance of different lipid particles, and the limited dietary impact on LP(a) levels.

Comprehensive evidence-based insights and practical recommendations for dietary patterns and cardiovascular health interventions are provided, offering clarity on these complex topics.

Note: This discussion is hosted by Simon Hill, and originally appeared as an episode of The Proof podcast.

Links:

• Subscribe to Sigma Nutrition Premium
• Receive our free weekly email: the Sigma Synopsis
• Episode with Professor Chris Packard

Timestamps:

• 07:19 Understanding Cholesterol and Lipoproteins
• 14:35 The Role of ApoB in Cardiovascular Risk
• 25:10 Atherogenic Lipoproteins and Their Impact
• 37:42 Causal Pathways and Biomarkers in Heart Disease
• 47:02 Understanding Residual Risk and Triglycerides
• 49:46 Paul Saladino’s Claims on LDL and Metabolic Health
• 01:03:01 Addressing Concerns About Lowering Cholesterol
• 01:16:16 The Importance of Early Intervention in Cholesterol Management
• 01:23:36 The Future of Cholesterol Management and Gene Editing
• 01:28:24 Atherosclerosis in Arteries vs. Veins
• 01:36:08 Dietary Interventions to Lower ApoB Levels
• 01:47:55 Modifying Keto Diet for Better Health Outcomes
• 01:56:33 Plant-Based Diets and Fat Consumption
• 02:05:10 Understanding Lp(a) and Its Impact on Health

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The consumption of red meat, specifically the distinction between unprocessed and processed varieties, has been a subject of considerable debate in nutritional science and public health. There is a fair amount of confusion and lack of clarity surrounding this issue.

While the harmful effects of processed meat are well-documented and less controversial, the evidence concerning unprocessed red meat is less consistent. This inconsistency often leads to a gray area in scientific discussions and public perception. In examining unprocessed red meat, we encounter a spectrum of claims, including minimal evidence of harm, context of overall diet and mechanistic concerns.

Epidemiological evidence shows varied health outcomes related to red meat consumption across different populations. These variations underline the importance of defining and measuring “high” and “low” intake levels accurately in research.

The challenges in nutrition research, including methodological flaws in meta-analyses and the rapid dissemination of simplified study results, can impact public health recommendations. Misinterpretations can arise from comparisons within narrow intake ranges or from studies failing to specify absolute intake levels.

This podcast episode’s goal is to clarify existing evidence, acknowledge areas needing further research, and explore why this topic is significant in the broader context of nutrition science, aiming to equip healthcare professionals with the knowledge needed to make nuanced and effective dietary recommendations.

Links:

• Receive our free weekly email: the Sigma Synopsis
• Want to advance your understanding of nutrition science? Check out our course.
• Go to episode page for this episode
• Subscribe to Sigma Nutrition PREMIUM

• 01:00 Introduction to the issue
• 03:16 Processed vs. unprocessed red meat
• 05:54 Health guidelines and recommendations
• 06:56 Epidemiological evidence and dose thresholds
• 09:55 Biological mechanisms and plausibility
• 21:00 Criticisms and misinterpretations in research
• 40:42 Substitution analyses and dietary patterns
• 46:37 Mendelian randomization and genetic studies
• 56:31 Effect modifiers and confounders
• 01:13:18 Key Ideas Segment (Premium-only)

Hypertension, commonly known as high blood pressure, is a silent yet prevalent health issue that affects millions of people worldwide. Often going unnoticed until significant damage has been done, hypertension can lead to severe cardiovascular complications if not properly managed.

Mechanistically, the causes of hypertension are complex, involving both genetic and lifestyle factors. The management of hypertension presents multifaceted challenges, encompassing both pharmaceutical treatments and lifestyle modifications.

From a prevention and management standpoint, understanding the interplay between genetics and lifestyle is crucial. This raises several important questions…

• To what extent do genetic factors contribute to hypertension risk compared to lifestyle choices, and how does this interaction influence disease progression?
• What role does lifestyle play in managing hypertension, and is there evidence supporting the influence of specific dietary patterns and nutrients, particularly sodium and potassium, on blood pressure control?
• How do exercise and physical activity impact blood pressure, and what types of exercise are most beneficial for individuals with or at risk of hypertension?
• What are the main categories of antihypertensive medications, and how do these drugs work to lower blood pressure?
• What are the potential side effects, and how should clinicians decide on the best treatment approach for individual patients?

In this episode, we are joined by Dr. Mohammed Alo, a board-certified cardiologist and internal medicine specialist, who will help us understand the intricacies of hypertension and how it can be effectively controlled.

Links:

• Go to episode page
• dralo.net/
• Receive our free weekly email: the Sigma Synopsis
• Subscribe to Sigma Nutrition Premium

Timestamps:

• 03:28 Dr. Alo’s Background and Expertise
• 08:40 Understanding Blood Pressure and Its Implications
• 10:26 Causes and Diagnosis of High Blood Pressure
• 12:42 Lifestyle Modifications and Treatment Options
• 30:26 Medications for Blood Pressure Management
• 38:34 Combination Therapy and Patient Variability
• 43:11 Debunking Myths About Sodium and Blood Pressure
• 57:29 Exercise and Lifestyle Interventions

Food science and behavior are intimately connected. One critical but often overlooked facet of this connection is food texture and its substantial impact on eating behavior and energy intake.

Food texture encompasses characteristics such as hardness and structure. It categorizes food into liquids, semi-solids, and solids, each with a wide range of textures—from dry and crispy to elastic and more substantial. This classification deeply affects how we consume food. The time it takes to chew and swallow a food item can vary greatly based on its texture.

Different textures can also influence the speed at which satiety signals are triggered. Eating rate is a highly individual trait, stable over time, and consistent across different contexts. Some people are naturally slower eaters, while others consume food quickly. This variance can have significant implications for energy intake and body weight.

In this episode, Dr. Marlou Lasschuijt, an assistant professor in the Sensory Science and Eating Behaviour group at Wageningen University, discusses the above topics and their implications.

Links:

• Subscribe to Sigma Nutrition Premium (for study notes and transcripts)
• Go to episode page
• The Restructure Project
• Receive our free weekly email: the Sigma Synopsis

• 00:14 Introduction
• 00:47 Dr. Lasschuijt’s Research Focus
• 04:23 Understanding Food Texture and Eating Behavior
• 06:37 Impact of Food Texture on Satiation and Eating Rate
• 16:55 Applications and Innovations in Food Science
• 18:31 Unanswered Questions
• 25:34 Practical Recommendations 
• 27:00 Current and Upcoming Research Projects

Cholesterol-lowering medications, particularly statins, play a pivotal role in reducing low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (apoB) concentrations, which are causal markers in atherosclerosis development. The efficacy of these medications is well-documented, with numerous clinical trials demonstrating substantial benefits in reducing cardiovascular events and improving overall mortality rates.

Despite the robust evidence supporting the benefits of cholesterol-lowering medications, there are various misconceptions and misunderstandings regarding their use. One common myth is that these drugs are unnecessary for those without overt cardiovascular symptoms, ignoring the preventative benefits for at-risk individuals.

Concerns about side effects, such as muscle pain, liver damage, and cognitive impairment, are often exaggerated. While side effects are possible, they are typically mild and manageable. Regular monitoring and adjustments by healthcare providers can help mitigate any adverse effects, ensuring that the benefits of reducing LDL-C and apoB far outweigh the risks.

In this episode, preventative cardiologist Dr. Paddy Barrett discusses the different types of lipid-lowering medications, their mechanisms of action, the side effects that may occur, and the misconceptions about the drugs that are unfortunately widespread.

Timestamps:

• 00:14 Introduction
• 03:26 Dr. Barrett’s Background
• 04:50 What is “Lipid Lowering”?
• 05:30 Overview of Lipids and Atherosclerosis
• 09:58 Setting Targets for Lipid Levels
• 15:52 Medications for Lowering LDL and ApoB
• 20:12 Statins: Types, Effects, and Side Effects
• 35:38 Addressing Concerns and Misconceptions
• 42:47 Future of Lipid Lowering Therapies

Links:

• Go to episode page
• Subscribe to Sigma Nutrition PREMIUM
• drpaddybarrett.com
• Dr. Barrett’s Substack
• Book: Heart. An Owner’s Guide
• Receive our free weekly email: the Sigma Synopsis

When aiming for healthy aging and reducing chronic disease risk over the lifecourse, exercise, specifically a combination of resistance training and cardiorespiratory fitness, has a fundamental role to play. In addition it can mitigate age-related declines and support independence in later years.

A strong evidence base exists showing the benefits of increased strength and cardiorespiratory fitness on a range of important outcomes related to lifespan and healthspan. But some intriguing questions remain, such as:

• How strong is strong enough?
• At what point do we maximize the benefits of exercise?
• How “fit” do we need to be?
• Is simple participation enough or do we need a true training adaptation?
• How can this actually be implemented in practice so that it is doable?

In this episode, Dr. Jordan Feigenbaum shares his insights on this topic and offers advice on how we can increase our probability of a long healthspan, through exercise interventions.

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• Barbell Medicine

Timestamps:

• 04:40 Dr. Feigenbaum’s Journey and Barbell Medicine’s Mission
• 05:57 Defining and Achieving Healthy Aging
• 10:37 The Impact of Exercise on Health and Longevity
• 28:52 Strength Training: How Much is Enough?
• 38:43 Muscle Mass vs. Strength: What Matters More for Health?
• 47:18 The Paradox of Muscle Mass vs. Strength
• 49:05 Designing an Effective Strength Training Program
• 01:01:27 Cardiorespiratory Fitness: Importance and Assessment
• 01:06:19 Optimizing Cardio Training: Intensity and Volume

Contemporary society is witnessing a growing interest in, and embracing of, plant-based diets. Numerous athletes are now gravitating towards such dietary choices, motivated by concerns for health, performance or ethics. Consequently, coaches, nutritionists, and other fitness experts find themselves increasingly tasked with guiding athletes who adhere to plant-based diets. For coaches and trainers, understanding the possible impacts of these dietary preferences on athletes’ objectives is paramount, as is devising dietary plans that optimize their performance. This episode discusses the scientific and practical aspects of supporting athletes who have adopted a vegetarian lifestyle and diet.

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The Food Frequency Questionnaire (FFQ) stands as a cornerstone in nutritional research, offering valuable insights into dietary patterns and habits over a specified period. Despite its widespread use and established utility, the FFQ has not been immune to criticism, much of which arises from a misunderstanding of its purpose and inherent limitations.

At its core, the FFQ is designed to assess the frequency and quantity of food consumption, aiming to capture long-term dietary behaviors rather than precise intake levels. Researchers employ it to investigate relationships between diet and various health outcomes, such as chronic diseases or nutritional deficiencies.

However, critics argue that its reliance on self-reported data introduces biases and inaccuracies, leading to potential misestimation of nutrient intake. Additionally, some detractors question the FFQ’s ability to capture sporadic or infrequent dietary choices accurately.

Yet, it’s crucial to recognize that the FFQ serves a specific purpose within the realm of nutrition research. While there are no doubt limitations, its strength lies in its ability to capture habitual dietary behaviors over an extended period. Moreover, researchers employ various strategies, such as validation studies and data adjustment techniques, to enhance the FFQ’s reliability and validity.

In this episode, world-leading nutrition epidemiologist Dr. Deirdre Tobias discusses the development of the FFQ, the key concepts that are crucial to understand, common criticisms of the FFQ, and how we should evaluate the utility of this tool.

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About This Episode:

“Personalized nutrition” has been promoted as an approach that will improve people’s health by prescribing them specific dietary recommendations based on their own genetic and phenotypic data.

The premise is that given we each respond differently to foods, having general dietary recommendations may be doing many people a disservice. And by using an array of personal data, it is now possible to give unique diets that improve health.

The early and interesting findings of research in this area was met with much fanfare, and indeed, many companies are now offering commercial direct-to-consumer services based on genetic and physiological testing, followed by “personalized” dietary prescription. Such testing may include genetic tests, microbiome testing, glucose monitoring data, and more. This data is then fed into machine learning algorithms to prescribe dietary recommendations.

However, do the marketing claims match the current evidence? Does the “proof” it works that is often cited, actually back up the claims? Do personalized nutrition diets actually lead to improved health outcomes over generic, conventional dietary recommendations? Do personalized nutrition diets lead to better outcomes than standard dietetic/nutrition practice?

To answer these questions, we go through the main studies cited in favor of personalized nutrition being superior to typical dietary advice, and see if they indeed support the claims.

So is personalized nutrition superior to standard dietary advice? Let’s find out…

Note: This was originally a Premium-exclusive episode. If you’d like to get more episodes like this, subscribe to Sigma Nutrition Premium.

The relationship between coffee and health is complex, encompassing areas like blood lipids, cardiovascular disease, neurodegenerative diseases, anxiety, and depression. Coffee has an interesting nutrient profile and contains diverse bioactive compounds that influence metabolism.

Coffee has a potential impact on cardiovascular disease risk, with mechanisms that highlight potential benefits and some concerns. There may be an impact on blood pressure and blood lipid, but there are important nuances to this.

Some research suggests that moderate intake may protect against neurodegenerative diseases like Alzheimer’s and Parkinson’s, with some mechanisms proposed for the observation. 

Coffee’s effects on anxiety, depression, and sleep are common talking points and worthy of addressing. The context of the consumption and the individual in question will dictate the likely effects. Ultimately, coffee’s effects on health are influenced by various factors, warranting personalized approaches to consumption.

In this episode, Simon Hill puts some questions to Danny Lennon about the impact of coffee on our health.

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• Simon's website: The Proof

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About This Episode:

Have you ever wondered how exercise affects our appetite and energy intake? While we know that single bouts of exercise can create a short-term energy deficit, do they also influence our hunger levels? And what about long-term exercise training? Could it modify our appetite in ways that help us better control our weight?

Recent research suggests that exercise may indeed play a role in appetite regulation. Could exercise modify the subjective and homeostatic mediators of appetite in ways that enhance our feelings of fullness after a meal?

One of the most fascinating aspects of this research is the variability in responses between individuals. Why do some people experience changes in appetite and energy intake after exercise, while others don’t? Could factors like adiposity, sex, or habitual physical activity levels play a role?

In this episode, Dr. James Dorling of the University of Glasgow helps us delve into the evidence surrounding how factors like adiposity, sex, and habitual physical activity modulate our responses to exercise in terms of appetite, energy intake, and appetite-related hormone responses.

About The Guest:

Dr. James Dorling is a lecturer in Human Nutrition at the University of Glasgow. Dr. Dorling’s research is broadly focused on three areas: (1) the impact of nutrition and physical activity interventions on obesity-related endpoints and biomarkers of aging; (2) the regulators of appetite and eating behaviours; and (3) the changes in appetite and eating behaviours in response to health interventions.

During his PhD, he studied the effects of acute exercise and obesity-related single nucleotide polymorphisms on appetite and appetite-related hormones. Following this, Dr. Dorling joined Pennington Biomedical Research Center where he worked as a postdoctoral researcher. His postdoctoral research principally focussed on the influence of calorie restriction and physical activity on weight, markers of aging, and eating behaviours.

In a world flooded with claims, advice, and recommendations on how to extend our lifespan, the buzz around various diet approaches, supplement regimens, and lifestyle hacks is deafening. But amidst the noise, one must pause to ponder: Are these claims rooted in science? And perhaps more crucially, are we even asking the right questions or pursuing the correct goals in our quest for longevity?

Join us in our upcoming podcast episode as Danny delves into these intriguing questions. Rather than getting lost in the sea of trends and fads, Danny offers his insights on the essential inquiries we should be making. Discover how to shift our focus towards the core factors that genuinely enhance our chances of leading longer, healthier lives. Don’t miss out on this thought-provoking exploration into the science and philosophy behind longevity.

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• NHS - National Health Service (UK)
• CAMHS eating disorder unit - Child & Adolescent Mental Health Service
• Tier 4 Services - CAMHS services are organized through a tiered system. Tier 4 is the highest on the hierarchy and relates to highly specialized or inpatient services.
• NG Feed - nasogastric (NG) tubes
• MDT decision - multidisciplinary team (MDT) decision-making
• CBT-E - Enhanced Cognitive Behaviour Therapy - a “transdiagnostic” treatment for all forms of eating disorder including anorexia nervosa, bulimia nervosa, binge eating disorder and other similar states​.
• ARFID - Avoidant/restrictive food intake disorder (ARFID) is a feeding or eating disorder in which people avoid eating certain foods, or restrict their diets to the point it ultimately results in nutritional deficiencies.
• SSCM - Specialist Supportive Clinical Management (SSCM) is a psychotherapy comprising a clinical management focus addressing anorexia nervosa (AN) symptoms and a supportive therapy component.

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• Course: Applied Nutrition Literacy
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About This Episode:

There has been much debate about the role of nutritional reductionism in research. This approach generally aims to study diet’s effects by breaking down the intricate web of dietary factors into smaller, more manageable components. But critics have asked does this approach truly capture the full picture of nutrition’s influence on our well-being?

In an attempt to help answer research questions there has been a proposal for the use of “nutritional geometry”, a framework that delves into the multidimensional relationships between nutrients and their effects on organisms. Within this framework, the protein leverage hypothesis emerges, proposing that our bodies prioritize protein intake and adjust food consumption accordingly. But how does this theory fit into the broader spectrum of nutrition science, and what implications does it hold for understanding and managing our diets?

Additionally, as aim to do better nutrition research, we are met with philosophical questions that challenge traditional reductionist views. Is it enough to simply dissect foods into their nutrient components, or do we need a more holistic understanding of dietary patterns and their impact on health?

In this episode, Prof. David Raubenheimer and Dr. Jonathan Sholl discuss the need to have an approach where science meets philosophy, and where reductionism meets synthesis. And we dive into ideas they have proposed that make a defense of some aspects of reductionism.

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About This Episode:

Sigma Nutrition is ten years old this week!

Over this time, I’m grateful for a wealth of insights garnered from interviews with some of the brightest minds in the field of evidence-based nutrition science.

Through these conversations, I’ve come to understand the critical underpinnings of scientific thinking, the importance of honing our critical appraisal skills, and the crucial distinction between accurate dissemination of information and misleading “half-truths”.

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About This Episode:

Navigating the vast landscape of research literature, particularly in the realm of nutrition science, presents numerous challenges for readers seeking to extract meaningful insights.

Before diving into research papers, individuals should have a precise understanding of the specific questions they seek to address. Without this clarity, there is a risk of wasting time on irrelevant studies or misinterpreting findings.

Furthermore, the selective approach to sourcing research is crucial. With countless studies available, employing heuristic strategies to filter out irrelevant ones and prioritize those aligned with research goals is essential.

Effectively reading nutrition studies requires a nuanced understanding of statistical concepts and methodologies used in various studies. Developing this understanding can be challenging, especially for individuals without a background in statistics or research methodology.

• How can individuals effectively navigate the vast volume of research literature to find studies relevant to their interests or research objectives?
• What are some common pitfalls to avoid when reading and interpreting nutrition science research?
• What role do external influences, such as media coverage or recommendations from experts, play in shaping perceptions of research findings?
• Are there specific strategies or tools that people can use to streamline their research process and optimize their time spent reading research papers?

In this episode, we discuss all these issues.

Course syllabus: Applied Nutrition Literacy

Questions Answered in This Episode:

1. [01:22] Do “low-carbers” need less vitamin C?
2. [14.56] If you were to advise a company to establish solid workplace health fundamentals, what would you tell them?
3. [26.20] Which compounds typically found in animal products would be interesting to supplement for health and performance purposes in vegan/vegetarian populations?
4. [40.09] In omega 3 supplementation studies it isn’t common to see a baseline measurement of omega 3 index. Why?
5. [44.10] What is your process for preparing for a podcast and choosing topics?
6. [49.53] Based on the current understanding, what is the most ideal diet for people to eat?
7. [55.26] Is there any evidence that otherwise healthy people should be consuming Omega 3 supplements?

This is a preview of is one of our Premium-exclusive AMA (ask me anything) episodes, where we answer questions submitted by Premium subscribers.

To listen to the full episode, you’ll need to be a Premium subscriber and access the episode on the private Premium feed.

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About This Episode:

The question of whether dietary fat quality causally affects atherosclerosis risk has been a subject of extensive research and debate within the field of nutrition and cardiovascular health.

Atherosclerosis, the build-up of plaque in arteries, is a key factor in the development of cardiovascular diseases, including heart attacks and strokes. Traditionally, dietary fat has been implicated in contributing to atherosclerosis, with a focus on reducing overall fat intake. However, recent studies have shifted the focus towards the quality of dietary fats rather than their quantity.

Not all fats are created equal, and researchers are now paying closer attention to the types of fats consumed in the diet. Saturated fats, commonly found in animal products and some tropical oils, have long been associated with increased cholesterol levels and atherosclerosis. On the other hand, unsaturated fats, including monounsaturated and polyunsaturated fats found in olive oil, nuts, and fish, have been linked to potential cardiovascular benefits. Research suggests that replacing saturated fats with unsaturated fats may have a positive impact on blood lipid profiles and reduce the risk of atherosclerosis.

Additionally, genetic factors and individual responses to different fats may play a role in how dietary fats impact atherosclerosis risk.

In this episode, Dr. Jacob Christensen discusses the research in this area and some conclusions about whether we can say dietary fat quality causally increases atherosclerotic cardiovascular disease (ASCVD) risk. This includes looking at the relationship between low-density lipoprotein (LDL) particles and ASCVD, the link between dietary fat quality and LDL particles, and then finally the relationship between dietary fat quality, LDL particles, and ASCVD.

About the Guest:

Jacob J. Christensen is a clinical dietitian and researcher at University of Oslo. His research interests include cardiovascular diseases, lipid metabolism, nutrition, genomics and data science.

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About This Episode:

There is a lot of interesting research going on related to plant-derived fatty acids, owing to their potential to help improve health and provide sustainable alternatives to other sources of healthy-promoting fatty acids.

In addition to work looking at the long-investigated alpha-linolenic acid (ALA), some research is now starting to look at more novel fatty acids like stearidonic acid (SDA), and pinolenic acid (PLA), each presenting unique structures and potential benefits within various plant sources. One intriguing focal point is Ahiflower oil, a distinctive source that harbors both ALA and SDA.

In this episode, Dr. Ella Baker of the University of Southampton discusses some of the science behind plant-derived fatty acids, offering a deeper understanding of their distinctive qualities, conversion pathways, and the captivating interplay between omega-3 and omega-6 fatty acids.

Dr. Baker’s research to date focuses on the metabolism, functionality, and underlying mechanisms of action of plant-derived fatty acids. Her interests include novel plant-derived fatty acids and exploring the effects on membrane structure and function.

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About This Episode:

Kidney stones, crystalline deposits formed within the kidneys, present a formidable challenge to individuals grappling with their debilitating effects. These mineral accumulations, though small in size, can inflict significant pain and discomfort as they navigate through the urinary tract.

Understanding the nuances of dietary management and treatment for kidney stones is crucial for those seeking relief and prevention.

What makes this subject particularly intricate is the diversity of kidney stones – a mosaic of compositions ranging from calcium oxalate to uric acid. Recognizing that not all kidney stones are created equal, dietitians and renal specialists tailor their recommendations to address the specific nature of the stones, unveiling a spectrum of dietary strategies that aim to alleviate symptoms and impede the recurrence of these insidious formations.

In this episode, specialist renal dietitian Deepa Kariyawasam brings us through the main causes of kidney stones, the potential dietary interventions, and how to guide individuals toward personalized pathways for kidney stone management.

• RDA = Recommended Dietary Allowance 
• AI = Adequate Intake 
• UL = Tolerable Upper Intake Level 
• EAR = Estimated Average Requirement

• Recommended Dietary Allowance (RDA)
• Adequate Intake (AI)
• Tolerable Upper Intake Level (UL)
• Estimated Average Requirement (EAR)

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About This Episode:

Alzheimer’s disease has a profound impact on individuals, families, and societies worldwide. As a progressive neurodegenerative disease, it not only robs individuals of their cognitive abilities but also places an immense emotional and economic burden on caregivers.

Mechanistically, the causes of Alzheimer’s are incredibly complex and not fully understood. And in terms of treatment, the landscape appears challenging. Drug discovery efforts for dementias, including Alzheimer’s, have faced setbacks, leaving a void in effective treatments. Consequently, attention has shifted toward preventive strategies, including dietary patterns.

From a prevention standpoint, both genetics and lifestyle should be considered. Which throws up many interesting questions…

To what extent do genetic factors contribute to Alzheimer’s risk compared to lifestyle choices, and how does this interaction influence disease development?

What role does lifestyle play in Alzheimer’s risk, and is there evidence supporting the influence of specific nutrients on cognitive health?

How do diet patterns impact Alzheimer’s risk? Are there discernible risk differences associated with specific dietary choices, and how do these interact with genetic factors, such as the ApoE genotype?

In this episode, Drs. Ayesha Sherzai and Dean Sherzai are on the podcast to answer these questions and discuss this topic in more depth.

About The Guests:

Dr. Ayesha Sherzai is a neurologist and co-director of the Alzheimer’s Prevention Program at Loma Linda University, where she leads the Lifestyle Program for the Prevention of Neurological Diseases. She completed a dual training in Preventative Medicine and Neurology at Loma Linda University, and a fellowship in Vascular Neurology and Epidemiology at Columbia University. She is also a trained plant-based culinary artist.

Dr. Dean Sherzai is co-director of the Alzheimer’s Prevention Program at Loma Linda University. Dean trained in Neurology at Georgetown University School of Medicine, and completed fellowships in neurodegenerative diseases and dementia at the National Institutes of Health and UC San Diego. He also holds a PhD in Healthcare Leadership with a focus on community health from Andrews University.

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About This Episode:

Numerous nutrition studies present findings of “no effect,” but interpreting such results requires caution. A null finding, indicating an absence of impact from a nutrient or exposure, may not necessarily suggest a lack of effect overall. Instead, it could stem from issues related to the study’s design, the nature of the exposure, or participant characteristics.

We’ve often referred to such studies as being “null by design”.

These studies, often termed “null by design,” may yield inconclusive results due to insufficient contrast in exposure levels to reveal a significant effect size. Additionally, participants’ baseline nutrient status or intake can contribute to false negatives. For instance, if a study provides a nutrient to individuals already replete in that nutrient, it may lead to an erroneous conclusion. This phenomenon can be understood by considering the bell curve of activity for a nutrient.

Moreover, a lack of methodological rigor can generate ‘false negatives.’ If previous literature indicates associations between high intake of a specific food or nutrient and certain outcomes, a study comparing levels of intake well below that threshold may produce a misleading result.

Some challenges arise from an overly reductionist perspective. In disease processes, reductionism simplifies diseases to a single primary source at the cellular and molecular level. This perspective assumes that if a nutrient shows a relationship with health or disease outcomes at a population level, its biological activity should manifest in isolation. However, applying such assumptions to exposures like diet may not be tenable.

In this discussion, we delve into the concept of “null by design” and present three specific studies with null findings, emphasizing the need for careful interpretation.

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• Crushing Comparisons course

About This Episode:

Social comparison theory, developed by psychologist Leon Festinger in the 1950s, posits that individuals determine their own social and personal worth based on how they stack up against others. This theory suggests that people engage in social comparisons to evaluate their abilities, opinions, and attributes, often choosing relevant others for comparison.

In the realm of body image and self-perception, social comparison theory becomes particularly pertinent, as individuals tend to assess their own bodies in relation to societal ideals and the bodies of others. This process of comparison can have profound implications for body dissatisfaction and the development of disordered eating patterns.

This raises thought-provoking questions about the impact of social comparison theory on body image and eating behaviors.

In this episode, Shannon Beer explores these questions and offers valuable insights into the complex interplay between societal influences, individual perceptions, and the development of body dissatisfaction and disordered eating.

About The Guest:

Shannon Beer is a registered nutritionist, health and confidence coach and certified Compassionate Mind Training facilitator.

Shannon works with people aiming to improve their health through facilitating lasting behaviour change in their approach to diet, exercise and body image.

She has developed a coaching framework that applies motivational interviewing, cognitive behavioral coaching, and acceptance and commitment therapy-aligned processes in a client-centered alliance toward their own values-based goals.

1. [02:16] How would you implement a calorie surplus for “bulking” in healthy trainees without compromising their health markers?
2. [15:25] If you were to advise someone with a heavy workload and busy schedule on how to establish the 80/20 of a healthy lifestyle, what would you tell them?
3. [24:36] Is coconut oil good or bad? What about claims that it cures cancer, Alzheimer’s, etc.?
4. [33:25] In the circumstance in which an individual has a normal ApoB yet an elevated LDL particle number, which value is more representative of risk?
5. [41:39] Should you supplement in order to reach 100% of RDA for micronutrients?
6. [46:35] Are raw oats a good ingredient to add to smoothies? Do they need to be cooked?
7. [51:58] Is there any research supporting whether or not diet really impacts oral thrush?
8. [55:21] Is there any benefit to supplemental collagen?

Note: This is a Premium-exclusive “ask me anything” episode. You can access the full episode as a Premium subscriber. Join here.

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• Instagram:
  • @jonosteedman
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About This Episode:

There is no shortage of misleading, confusing and even dangerous nutrition information on the internet. And, unfortunately, much of it can sound very convincing and appealing to people who wish to improve their health. The result can be that they may end up ironically doing the opposite.

At an individual level, dietitians and medical practitioners end up having to work with patients who have heard incorrect information or who have been following poor advice.

What issues does this present? What is the most productive way to help patients and clients in this situation? How can we help give better information while also listening and caring for the patient?

To discuss such questions, dietitian Jonathan Steedman is on the podcast to share his experiences and approaches to spreading evidence-based information in a palatable and productive manner.

About The Guest:

Jonathan Steedman is an Acredited Practising Dietitian (APD) in Australia. He currently works with patientes via telehealth services. He is well-known on social media for explaining confusing nutrition topics in a way that is understandable and engaging for the general population.

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About This Episode:

Insufficient energy availability can significantly disrupt normal hormonal, metabolic, and physiological processes, prompting the body to initiate a coordinated response aimed at conserving energy.

While commonly viewed as beneficial for weight loss and managing cardiometabolic conditions in the current obesity epidemic, chronic energy deficiency in the context of modern sports and exercise nutrition is linked to adverse health outcomes and diminished athletic performance.

Nevertheless, the evidence regarding the negative impact of energy deficit on physical capacity and sports performance is not entirely clear.

Although severe energy deficiency can impair physical capacity, it’s noteworthy that humans can enhance aerobic fitness and strength even in the presence of significant energy deficits. Strikingly, many elite athletes compete at the highest levels despite displaying evident signs of energy deficiency.

This raises intriguing questions about how the human body adapts to energy deficits, challenging conventional views on the relationship between energy availability and athletic prowess.

To discuss some potential reasons for this ability to maintain peak physical performance while suppressing energetically demanding physiological traits, researcher Dr. Jose Areta of LJMU is on the podcast to discuss his work in this area.

About The Guest:

Dr. José Areta currently works as a lecturer in Sports Nutrition and Metabolism at the School of Sport and Exercise Sciences at LJMU.

José’s primary interest is in the area of training-nutrient interactions in humans. In other words, he investigates how to manipulate ingestion of carbohydrates, fat and protein around training to optimise physical performance and health.

The outputs of his research have not only expanded the knowledge of the field but had significant impact and influence on determining current dietary recommendations and practices world-wide.

His work has provided novel insights in relation to the amount, timing, quantity and distribution of carbohydrates, fat and protein and dietary supplements around training. Over the last few years José has been developing his research in the area of the endocrinological, metabolic and physiological effects of energy restriction, in which he is currently growing his research team and capability.

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About This Episode:

The Portfolio diet is a nutritional approach that has garnered attention for its ability to reduce blood lipids and thus improve cardiovascular health.

While past intervention trials have demonstrated significant reductions in blood lipids, a critical aspect often overlooked is the long-term impact, both in terms of adherence and disease outcomes.

A recent study aimed to address this by looking at disease risk across three cohorts: the Nurses’ Health Study I, Nurses’ Health Study II, and the Health Professionals Follow-up Study.

The study made use of a Portfolio Diet Score (PDS), a comprehensive metric that evaluates the diet’s efficacy based on specific components.

These components include positive rankings for plant proteins (especially from legumes), nuts and seeds, viscous fiber sources, phytosterols (mg/day), and plant monounsaturated fat sources. Conversely, the PDS negatively ranks foods high in saturated fat and cholesterol.

In this episode, Dr. Andrea Glenn, the lead author of this study, discusses the intricacies of the research, providing insights into its findings and shedding light on how these findings resonate within the broader landscape of literature.

This episode is one of our Premium-exclusive AMA (ask me anything) episodes, where we answer questions submitted by Premium subscribers.

To listen to the full 90 minute episode, you’ll need to be a Premium subscriber and access the episode on the private Premium feed.

Otherwise, you can hear a preview of the episode here.

Full List of Questions:

1. [01:50] How should one interpret the systematic reviews done by Hooper et al that report no association between modification or reduction of saturated fat intake with cardiovascular mortality, total mortality, non-fatal MI?
2. [22.10] Given most people don’t meet them, are public health targets for fruit and vegetables too high?
3. [29.10] What is the role of homocysteine in heart disese? Is it causal?
4. [40:45] Monounsaturated Fat: Good, Bad or Indifferent?
5. [50:13] Is there evidence to suggest an upper limit for BMI, where even individuals with a ‘healthy’ body composition would be at elevated risk?
6. [59:32] Where does the current research stand on the impact of diet on brain health?
7. [01:08:48] Based on recent findings, do we have to throw out previous research on diet’s impact on the gut microbiome?

Links:

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• Sigma's Recommended Resources

About This Episode:

Navigating the intricate landscape of sports nutrition is one that constantly evolves and challenges our understanding of optimal athletic performance.

The delicate balance between advancing research and ensuring practical applicability in the high-speed realm of sports nutrition is a perpetual struggle.

Decision-making is difficult, especially when faced with a scarcity of evidence. It’s a challenge that resonates with many professionals in the field, prompting reflections on the art of making informed choices in the absence of conclusive data.

In this episode, Dr. Andy Kasper, PhD shares his experiences and research in the field of elite sports nutrition.

Dr. Kasper, a PhD in Nutrition and Physiology from Liverpool John Moores University, currently spearheads the Performance Nutrition department at Newcastle United Football Club. His illustrious career spans across elite football, rugby union, and rugby league, with notable stints at clubs like Chelsea, Fulham, Derby, England Rugby Union, Sale Sharks, London Irish, and Wasps, to name a few.

A prolific contributor to academic publications, Dr. Kasper’s insights have not only shaped the scientific landscape but have also directly influenced the nutritional strategies employed by top-tier athletes.

Our conversation will traverse a myriad of topics, from the transformative changes witnessed in sports nutrition to invaluable advice for practitioners navigating this intricate terrain.

We’ll also delve into the delicate balance between advancing research and ensuring practical applicability in the fast-paced world of sports nutrition. Dr. Kasper will shed light on the Paper-to-Podium Matrix, a concept that bridges the gap between scientific discoveries and their real-world implementation in the pursuit of athletic excellence.

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About This Episode:

The Oslo Diet-Heart Study was one of the earliest randomized controlled trials to explore the relationship between diet and heart disease. It aimed to investigate the impact of dietary interventions, specifically the reduction of saturated fat intake and an increase in polyunsaturated fat intake, on cardiovascular health.

The Oslo Diet-Heart Study involved 412 men who had already suffered a myocardial infarction 1-2 years before the start of the intervention.

Despite some known limitations, the Oslo Diet-Heart Study played a role in shaping early understanding on the relationship between dietary fat, cholesterol levels, and heart disease. Subsequent research and larger studies have contributed to a more nuanced understanding of the complex factors influencing cardiovascular health.

In this episode we discuss why this trial is important in the history of diet-heart research and how it connects to other seminal work in the field.

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About This Episode:

In 1959 a landmark clinical trial, often referred to as the LA Veterans Study, began with the aim to investigate the effects of replacing dietary saturated fats with polyunsaturated fats, on the progression of atherosclerosis and cardiovascular outcomes.

This was an eight-year clinical trial in 846 domiciled male veterans in the US. The diets between the control and experimental groups differed by saturated fat and polyunsaturated fat (particularly linoleic acid) content, but were similar in calories and total dietary fat.

The findings of the study suggested that replacing saturated fat with polyunsaturated fat was beneficial for reducing heart disease risk. However, the study also reported an unexpected increase in non-cardiac mortality in the intervention group, which raised concerns.

In this episode, we discuss why the LA Veterans Study was such a seminal trial and what we can learn from it.

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About This Episode:

The Lyon Diet Heart Study (LDHS) is often cited as one of the pivotal studies that helped establish the Mediterranean diet as a recognized and recommended dietary pattern for cardiovascular health.

A clinical trial conducted in Lyon, France, the LDHS showed significant reduction in cardiac death could be achieved in secondary prevention patients using a dietary intervention.

Conducted between 1992 to 1996, the study involved 605 participants who had previously experienced a heart attack (myocardial infarction).

LDHS showed an incredible 75% lower risk of cardiac death in these patients. This remarkable reduction was unexpected and led to considerable attention from the medical and scientific communities.

LDHS is interesting to dig into for several reasons. First, it’s clever methodology was able to account for some challenges of doing nutrition research. Second, the dietary intervention, whilst named as a “Mediterranean diet”, should perhaps be considered differently.

In this episode, Alan and Danny dig into all the details, highlighting some important lessons we can take from LDHS.

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• Past episodes referenced: Episodes 493, 481 & 317
• Further reading: How Diet Influences Heart Disease Risk

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The Sydney Diet-Heart Study was a clinical trial conducted in the 1960s and 1970s that aimed to examine the hypothesis that reducing saturated fat intake in the diet would lead to a reduced risk of heart disease.

However, it really only gained attention after a more recent re-analysis by Ramsden et al., which in recent years has been used as supporting evidence for the idea that increased polyunsaturated fat (PUFA), and specifically linoleic acid, in addition to reduced saturated fat intake, can increase heart disease risk.

This was based on the findings that substituting linoleic acid in place of saturated fat increased all-cause, CVD and CHD mortality.

This is of course counter to prevailing consensus and guidelines in this area, which routinely show reduced risk on replacing SFA with PUFA.

Could this trial undermine the common conclusions that replacing saturated fat with polyunsaturated fat decreases heart disease risk?

In this episode Alan and Danny discuss some of the crucial aspects to understand about this study and what it means for what conclusions can be made about the impact of PUFA broadly, and linoleic acid specifically, on our health.

Note: This is a Premium-exclusive episode, so in order to listen to the full episode you’ll need to subscribe to Sigma Nutrition Premium. 

Nutritional epidemiology has faced strong criticism over time. While some of the methodological limitations are fair, often there are criticisms that are misguided and inaccurate.

In this episode, Danny touches on a few examples of the misunderstandings of the field and how such claims can be addressed in a more accurate manner.

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The field of research exploring sex differences in exercise response has yielded intriguing findings, shedding light on the complex interplay between biology, physiology, and training adaptations.

One of the fundamental areas of investigation pertains to sex disparities in strength, power, and hypertrophy. Historically, it’s been well-established that males, on average, exhibit greater absolute strength and muscle mass compared to females. This discrepancy often traces its roots back to inherent physiological distinctions.

However, when it comes to responses to strength and hypertrophy training, the narrative becomes more nuanced. Research indicates that, when individuals of both sexes follow matched resistance training protocols, the relative improvements in strength and hypertrophy are quite similar.

So, do women need to be trained differently than men? The answer, it appears, is not as much as one might assume. The principles of progressive overload, specificity, and other training fundamentals remain constant. While individualization is key, the idea of drastically distinct training guidelines based on sex lacks compelling empirical support.

The guest in this episode, Dr. David Nolan, is a researcher in the area of sex differences in exercise response, and has looked at the influences of menstrual cycle and hormonal contraceptive use in female athletes on their performance.

In this episode, we discuss the research to date, and what this means practically for athletes and coaches.

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• SNP17: Is Personalized Nutrition Superior to General Nutrition Advice?
• 414: Will Machine Learning Overtake Traditional Nutrition Research Methods?
• 469: Chrononutrition – New Findings & Updated Views

• Outstanding questions in nutrition science
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Sensory cues, comprising taste, smell, texture, and appearance, serve as the initial drivers that influence our food preferences and liking for particular items. These sensory cues can be both inherent, such as the natural sweetness of fruit, and learned, as in the association between a particular aroma and a favorite dish.

One crucial aspect of this research is delving into how sensory properties of food, like texture and taste, contribute to our choices and consumption patterns. Food texture, for example, plays a key role in determining how quickly we consume a meal, with softer textures often being associated with faster eating rates.

Sensory intensity and palatability are also central themes in this research. Moreover, research into dietary fat reveals intriguing phenomena like “fat blindness,” where the ability to discriminate different levels of fat diminishes as taste intensity increases. Understanding these relationships can help shed light on factors contributing to overeating and potential avenues for behavior modification.

To give us a better insight into this field of research, Professor in Sensory Science and Eating Behavior at Wageningen University, Prof. Ciarán Forde, is on the podcast to discuss these ideas.

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PREDIMED (Prevención con Dieta Mediterránea) is a landmark clinical trial conducted in Spain.

The study made a huge splash due to the rarity in nutrition of having large RCTs with hard endpoints. In addition, it had results of a large magnitude; showing a 30% reduction in cardiovascular events.

But the study did face criticisms and controversies over methodological issues, including randomization procedures at certain centers, ultimately leading to a retraction of the original paper and a re-analysis.

Participants in the PREDIMED trial were randomly assigned to one of three groups:

• A Mediterranean diet supplemented with extra-virgin olive oil.
• A Mediterranean diet supplemented with mixed nuts (walnuts, almonds, and hazelnuts).
• A control group following a low-fat diet.

Despite the issues it still ends up being an incredibly useful source of data.

In this episode we discuss the findings from PREDIMED, some of the potential limitations, and where it sits among the wider Mediterranean Diet literature.

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The PROPEL (Promoting Successful Weight Loss in Primary Care in Louisiana) trial was a cluster-randomized weight loss trial, specifically tailored to address the pressing health concerns of an underserved population in Louisiana, where obesity rates have reached alarming levels.

The core of the intervention comprises a pragmatic, high-intensity lifestyle-based obesity treatment program, thoughtfully designed to be integrated within primary care settings. Over a 24-month duration, this multi-component weight loss program is delivered by skilled health coaches who are embedded in primary care clinics, with the aim of instigating substantial and sustainable weight loss outcomes.

In this study, 803 participants were enrolled, of whom 67% identified as Black and 84% as female, thereby ensuring a diverse representation. The research design randomized 18 clinics, allocating them equally into two groups: usual care and an Intensive Lifestyle Intervention (ILI). The usual care group continued to receive their customary primary care, serving as the benchmark against which the ILI’s efficacy will be measured.

In this episode we have the opportunity to delve deeper into the intricacies of the PROPEL trial and gain insights from one of its lead researchers, Dr. John Apolzan of the Pennington Biomedical Research Center.

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Food frequency questionnaires (FFQs) have been widely employed in nutrition research to assess dietary intake patterns among study participants. However, debates surrounding the reliability of FFQs have persisted both inside and outside the academic community.

These debates primarily revolve around issues related to measurement error, recall bias, and the appropriateness of FFQs for diverse populations.

One prominent concern is the potential for measurement error in FFQs. These questionnaires rely on self-reported data from participants, which can introduce inaccuracies due to memory limitations and social desirability bias. Participants may not accurately recall their food consumption frequencies and portion sizes, leading to imprecise estimates of nutrient intake.

Recall bias is another critical issue in the reliability debate. Participants may selectively remember or misreport the consumption of certain foods or nutrients, leading to an overestimation or underestimation of actual dietary intake.

Two concepts are crucial to understand: validity and reproducibility. FFQs are validated by cross-referencing the FFQ data with other dietary assessment tools (or other methods). It’s also important to consider if an FFQ gives reproducible results when used on multiple occasions.

When we ask “are FFQs reliable?”, we must first understand the conceptual exposure of interest: average intake over time. Second, we must consider what nutrients we are looking at. And third, in what population.

In this episode, Danny & Alan discuss the reliability of FFQs and how to have a deeper, more accurate understanding of their use. They take a look at valid critcisms of FFQs, as well as some of the more ill-informed criticisms.

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In 1985 a paper titled “Sick Individuals and Sick Populations” was published in the International Journal of Epidemiology.

The paper, authored by eminent epidemiologist Geoffrey Rose, can be considered as seminal and important because it brilliantly raised the concept of the “prevention paradox” and challenged traditional approaches to public health and preventive medicine.

The paper’s insights have had a lasting impact on how we understand and approach population health interventions. And it raised many contentious public health issues, which are still debated and relevant today.

The ideas have very important implications for how we can tackle diet-related diseases in meaningful ways.

In this episode, Danny and Alan discuss the central themes of the paper, why they are so crucial to understand, and what this means for our understanding of diet and chronic disease prevention.

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The Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (ATBC) stands as a seminal and pioneering research endeavor within the domain of epidemiology and cancer prevention. Conducted in Finland, the study aimed to examine the potential protective effects of alpha-tocopherol (vitamin E) and beta-carotene supplementation against the occurrence of various cancer types, particularly lung cancer, among male smokers. Initiated in the early 1980s, the study’s comprehensive design, rigorous methodology, and its focus on a specific high-risk population have contributed significantly to the understanding of the interplay between dietary antioxidants and cancer risk.

The ATBC study was founded on a growing body of evidence suggesting the potential role of antioxidants in mitigating the deleterious effects of oxidative stress and free radical damage, which are recognized as contributors to carcinogenesis. The selection of male smokers as the study cohort was strategically significant, given the heightened susceptibility of this group to lung cancer and other malignancies due to the synergistic action of smoking and oxidative stress. The study’s rigorous double-blind, placebo-controlled design ensured a high degree of scientific rigor, minimizing biases and confounding factors that might influence the outcomes.

One of the primary reasons for the study’s seminal status is its contribution to the understanding of the complex relationship between antioxidants and cancer risk. While the study did not find a significant reduction in lung cancer incidence among the intervention group receiving alpha-tocopherol and beta-carotene supplements, its findings spurred critical discussions within the scientific community. The neutral or inconclusive results underscored the intricate nature of carcinogenesis and highlighted the limitations of simplistic cause-and-effect interpretations in the context of cancer prevention. Moreover, the ATBC study contributed to a shift in research paradigms, prompting scientists to explore broader dietary and lifestyle factors that influence cancer risk beyond single-nutrient interventions.

In this episode we discuss the three most important publications from the study, with a specific look at what crucial lessons they teach us about the nuances, challenges, and unique aspects of nutrition as a scientific field.

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The field of circadian biology has long been associated with regulating diurnal physiological processes, notably the sleep-wake cycle. However, recent advances have unveiled a broader role for circadian clocks across various tissues, including skeletal muscle.

Within this context, the investigation of circadian clocks within the skeletal muscle milieu has emerged as a frontier of scientific inquiry. These intrinsic timekeeping mechanisms exhibit multifaceted regulatory capacities beyond mere temporal synchronization.

This episode delves into the implications of “circadian clocks” operating within skeletal muscle tissue, with the esteemed Prof. Karyn Esser as this week’s guest. Her pioneering work has been instrumental in understanding the interplay between circadian rhythmicity and muscular physiology.

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The Multiple Risk Factor Intervention Trial (MRFIT) was a groundbreaking clinical trial conducted in the 1970s and 1980s. Its main objective was to investigate the relationship between various risk factors and the incidence of heart disease.

The study aimed to determine whether modifying risk factors, such as high blood pressure, high cholesterol levels, and smoking, could lead to a reduction in cardiovascular events.

The trial spanned several years, with participants being followed up for a period of approximately six years to assess the incidence of cardiovascular events and mortality. The primary outcome measures included coronary heart disease (CHD) mortality and overall mortality.

The MRFIT trial yielded several important findings that have significantly influenced our understanding of cardiovascular health and prevention strategies.

In this episode we take a look at why this is such seminal research, as well as the contribution of one of the greatest researchers ever in the field, Jeramiah Stamler.

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One of the most important and influential papers in nutrition science is one by Ancel Keys and his colleagues that was published in The Lancet in 1957. This seminal paper examined the relationship between dietary fat intake and serum cholesterol levels. The researchers investigated how different types of fats in the diet affected cholesterol levels in a series of their previous tightly-controlled dietary experiments..

Those studies involved feeding the participants various diets with different compositions of fats. The researchers analyzed the participants’ blood samples to measure changes in serum cholesterol levels in response to dietary changes.

The most important aspect of this paper is the presentation of the ‘Keys Equation’; a predictive equation for the impacts of saturated, monounsaturated, and polyunsaturated fats, and dietary cholesterol, on blood cholesterol levels.

Crucially, the Keys Equation identifies the importance of the ratio of polyunsaturated to saturated fats in the diet; known as the ‘P:S ratio’. It showed that the P:S ratio is the most important dietary factor impacting blood cholesterol levels. And specifically that saturated fats increase total and LDL cholesterol twice as much as polyunsaturated fats lower them.

The findings of this study were significant in highlighting the potential impact of dietary fat subtypes on serum cholesterol levels and heart disease risk. It contributed to the growing body of evidence supporting the hypothesis that high serum cholesterol levels, particularly due to a diet rich in saturated fats, were associated with an increased risk of cardiovascular diseases.

In this episode, as part of our new series taking an in-depth look at seminal nutrition studies, we go through this influential paper from Keys, Anderson and Grande.

This is a Premium-exclusive episode, so here you'll only hear a preview. In order to listen to the full episode you’ll need to subscribe to Sigma Nutrition Premium.

About This Episode:

It has been clearly demonstrated that elevated LDL-cholesterol (LDL-C), or perhaps more specifically pro-atherogenic lipoproteins, is causal in atherosclerosis development in humans.

One crucial concept within this is that the risk relates not only to the magnitude of elevated LDL-C, but the duration of exposure. Thus, the role of LDL-C in driving atherosclerosis is referred to as a “cumulative, integrated exposure over the lifecourse”.

But, what exactly does this mean?

In this episode, Danny discusses the cumulative exposure model of LDL-C in atherosclerosis, the evidence supporting it, and the implications of this for the “debates” that get raised in relation to LDL-C (or apoB-containing lipoproteins) and heart disease.

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Losing at least 5% of one’s initial body weight is associated with improvements in glycaemic control, blood pressure, triglyceride levels, and other positive outcomes. Due to these reasons, it is typically recommended that individuals classified as overweight or obese should engage in effective weight loss interventions.

However, despite the potential for clinically significant weight loss through these interventions, weight regain is a common occurrence. This can be attributed to a combination of low adherence to weight control strategies and compensatory physiological mechanisms that influence weight regain.

Consequently, this may result in a cycle of losing and regaining weight over the long term, which is commonly referred to as “weight cycling.”

There are concerns regarding the potential harm to health and increased risk of chronic diseases associated with weight cycling. Some mechanisms have been proposed, such as the loss of lean mass during weight loss periods that is not regained when weight is regained. However, the evidence supporting the harmful effects of weight cycling on health is incomplete and many unanswered questions remain.

In this episode, we will examine the evidence published to date and draw evidence-based conclusions regarding the impact of weight cycling on long-term health.

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There has been interest in, and debate about, how protein intake impacts metabolic health, particularly in relation to insulin resistance and type 2 diabetes risk.

Recently, there has been interest in higher protein intakes as an intervention in diabetes, owing to a variety of potential mechanisms. For example, the satiety value of protein, the promotion of insulin secretion by protein, and imapcts on incretin hormones.

However, others have warned against high protein intakes. With some going as far as to claim high, or even moderate, protein intakes can lead to insulin resistance or negatively effect beta-cell function.

In this episode, we look at the research typically cited in support of such claims, and dig into the details. We consider the overall evidence in this area to answer the question ‘do high protein diets cause insulin resistance or increase diabetes risk?’.

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We've just released a lengthy 'ask me anything' episode, where Dr. Alan Flanagan addressed specific listener questions, over on the Sigma Nutition Premium feed. In this episode, you'll hear one detailed answer from that AMA, in which Alan discusses the concept of "causal risk factors".

This is a term that is regularly mentioned on the podcast, and has a very specific and important meaning. This episode will give you an in-depth understanding and comfort with the term, which will enhance your future understanding and learning.

If you wish to hear the other 10 questions Alan answered, you can subscribe to Sigma Nutrition Premium here.

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In the UK, there is a threefold higher incidence of type 2 diabetes in UK African and Caribbean (AfC) communities, compared to the general population. And ethnic inequalities in type 2 diabetes treatment and outcomes have been documented. And so addressing these inequalities is an urgent healthcare priority in the UK.

Differences in outcomes relate to physiological differences as well as pragmatic issues and structural barriers. Professor Louise Goff has done pioneering work in relation to both aspects.

Prof. Goff’s research has highlighted ethnic differences in type 2 diabetes pathophysiology between those in UK African and Caribbean groups and white Europeans. This means that typical screening for diabetes may not be as useful for AfC communities, in addition to treatments not being as appropriate.

In addition, there are noted differences in engagement with diabetes education services and self-management advice. This may be due to the fact that the delivery of information is not culturally relevant to those in AfC communities. And so diabetes structured education programs have been found to be less successful in people from minority ethnic groups.

Prof. Goff has attempted to address this by developing a culturally tailored self-management education and support program for type 2 diabetes in black-British adults. This program, called the Healthy Eating and Active Lifestyles for Diabetes (HEAL-D) program, has initially been trialed with local Black African and Caribbean communities and healthcare providers in South London.

In this episode, Prof. Goff discusses the ethnic differences in diabetes pathophysiology and the other factors underlying the inequalities in diabetes outcomes in black African and Caribbean communities.

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The topic of whether hunger and satiety are affected by the time of day has generated considerable interest within the nutrition research community. Researchers have been particularly intrigued by the potential influence of circadian rhythms on caloric intake throughout the day.

Initially, a number of studies proposed that consuming high energy intakes in the morning could lead to significantly greater weight loss compared to evening consumption. And while much attention was placed on the hypothesis that differences in expenditure were the cause, more recent research has called that into doubt.

And so, it is crucial to consider the possibility that other factors may be contributing to the outcomes observed in the intervention trials. In recent years, a series of papers has suggested an alternative explanation; the impact of time-of-day energy intake on appetite and hunger.

In this episode, Alan and Danny take a look at the current evidence related to this connection between time-of-day, appetite, and energy intake. And then, from that, what does this mean for how calorie distribution may affect dietary intake, body composition and health.

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“Weight cutting” is a common practice in weight-class based sports. And typically, combat sport athletes have reported cutting the largest amounts of weight for competition.

The concept of cutting weight is based on the assumption that a size advantage gives a performance advantage in combat sports. And by getting into a lower weight class than their “normal” weight, athletes can enjoy an advantage (or, more accurately, not be at a disadvantage).

The decrease in weight from an athlete’s habitual weight to their weight-class limit typically has two phases: a chronic weight loss phase (gradual dieting to lose fat mass), and an acute weight loss phase (rapid declines in weight due to losses of water, glycogen and gut residue).

To discuss the science, practical application and dangers of weight cutting strategies, performance dietitian Jordan Sullivan is on the podcast.

Jordan has been the performance dietitian for several years to Israel Adesanya, Alexander Volkanovski, Leon Edwards, Dan Hooker, Kai Kara-France, and many other well-known names.

And he is the co-author, along with Danny, of the new textbook ‘Making Weight: The Ultimate Science Based Guide to Cutting Weight for Combat Sports’.

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Peaks in blood glucose (or “blood sugar spikes”) are commonly highlighted as something harmful to health. And, of course, an excessively high blood glucose response to a meal can be problematic, or at least indicate there is a problem.

However, elevations in blood glucose after eating are a normal physiological response. And “bad” blood glucose responses are those that stay high for a prolonged period; i.e. after elevating, they don’t return to normal within an appropriate period of time.

But now many normoglycemic people are worrying about normal blood glucose responses, due to information that portrays even moderate elevations in blood glucose as harfmul. To add to the confusion, people are looking at standardized cut-off thresholds for diabetes and pre-diabetes, and mistakenly using them to label their own response to eating as measured by a continuous glucose monitoring (CGM) device.

When it comes to normoglycemic people, there is still a grey area in relation to how much of a glucose spike is a cause for concern. And given that there are still open questions that evidence has not fully answered yet, there is room for different interpretations of how to answer this question.

So what actually is a blood glucose peak that is “too high”? Is it 7.8 mmol/L (140 mg/dL)? 10.0 mmol/L (180 mg/dL)? 11.1 mmol/L (200 mg/dL)? Or do we even need to think about this once standard measures (e.g. HbA1C) are normal?

To discuss this interesting area, Dr. Mario Kratz and Dr. Nicola Guess are on the podcast to offer some perspectives and their conclusions from the current evidence base.

Blood Glucose Unit Conversions:

• 1.7 mmol/L = 30 mg/dL
• 7.0 mmol/L = 126 mg/dL
• 7.8 mmol/L = 140 mg/dL
• 9.0 mmol/L = 162 mg/dL
• 10.0 mmol/L = 180 mg/dL
• 11.0 mmol/L = 198 mg/dL
• 11.1 mmol/L = 200 mg/dL

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Menopause is commonly associated with hormonal changes and physical symptoms, such as hot flashes, mood changes, sleep issues, and weight gain. Based on anecdotal reports, another interesting question emerges: what is the potential impact of menopause on appetite?

As women undergo this transformative phase, many report fluctuations in their food intake and body weight, raising the question: Does menopause alter appetite?

Understanding the relationship between menopause and appetite is of great significance, as it can potentially provide insights into the mechanisms behind weight gain and obesity risk that often accompany this stage of life. Furthermore, comprehending the factors that contribute to changes in appetite during menopause could aid in the development of tailored interventions and strategies to support women’s overall health and well-being.

In this episode, we delve into the research to see if we can unearth any answers. What studies have been done? What results do we see? What conclusions does this allow us to make? And what does future research need to do in order to provide better answers?

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Note: This is a Premium-exclusive episode, so in order to listen to the full episode you’ll need to subscribe to Sigma Nutrition Premium. 

Low-carbohydrate diets come with a list of reported benefits, and research does show benefit for a number of different outcomes. However, many influencers and advocates of low-carb diets routinely add commentary that is misleading, incorrect, and possibly dangerous. This has led to us highlighting such incorrect information on this podcast before and pushing back against central claims of the “big names” in the “low-carb community”.

However, low-carbohydrate diets can indeed be a viable dietary pattern for people who wish to consume a healthy diet… provided they meet a few criteria. In other words, it is possible to consume a low-carb diet that still largely fits in with the evidence we have on healthy dietary patterns.

In this episode, Danny discusses what health outcomes may result from low-carb diets, and what distinguishes a “healthy low-carb diet” from an “unhealthy low-carb diet”. This includes some pragmatic tips for nutritionists, health professionals and consumers, who are choosing to use a low-carbohydrate diet.

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Metabolic adaptation refers to the process by which the body adjusts its metabolism in response to changes in energy intake or body mass. This adjustment can occur in both directions, meaning that the body can increase or decrease its energy expenditure in response to changes in energy intake or body weight.

When someone consumes fewer calories than their body requires for energy, the body will respond by slowing down its metabolism to conserve energy. This can make it harder to lose weight and maintain weight loss over time. Conversely, when someone consumes more calories than their body needs, the body will increase its metabolic rate in order to burn off the excess energy.

There are several open debates in science about metabolic adaptation, including the actual magnitude of it, its relevance to weight loss, what measurement methods should be used, and the mechanisms underlying the contributory factors.

Some people have framed metabolic adaptation as so significant that it makes weight loss attempts futile. While others, including in research, have referred to metabolic adaptation as an “illusion”. So what do we actually know about this concept and what is the pragmatic significance of it?

To discuss the nuances of the topic, Alan and Danny are joined by Dr. Eric Trexler, who has published on this topic and has followed recent publications closely.

About The Guest:

Dr. Eric Trexler is Director of Education at Stronger By Science, where he co-hosts the SBS podcast. He also is one of the four contributors to the MASS Research Review.

Eric has a prolific background in exercise science research, with more than 30 publications to his name by the time he completed his PhD at UNC-Chapel Hill.

---

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The benefits of consuming a higher fiber diet have been consistently demonstrated in nutrition research. Epidemiology clearly shows that higher intakes, compared to lower intakes, leads to a risk reduction for a range of diseases, including cardiovascular disease and colon cancer.

And based on this epidemiological evidence, most dietary guidelines recommend dietary patterns that provide adults with 30-35g of dietary fiber per day.

However, what do we know about intakes beyond this?

Do we continue to see benefit in a linear fashion? Is there a ceiling to benefit? At what level would we see “optimal” benefit or the greatest magnitude of risk reduction?

The ability to answer such questions is hampered by the fact it’s difficult to find cohort studies where the “high” fiber level is high enough to relate to this issue. However, there have been some controlled studies looking specifically at “very high” intakes, i.e. those far above current recommendations. In addition, there are some populations where habitual dietary intake gives a fiber intake far above the typcial intakes in Western cohorts.

So in this episode we go through this data to try to see what we can conclude about this fascinating question of ‘what are the health effects at very high fiber intakes?’

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In the last couple of decades, carbohydrates have experienced an increasing amount of negative campaigning. In general, the main argument is that carbohydrates have been viewed as the root cause for obesity, diabetes and several other diseases including heart disease and behavioral disorders. However, there can often be a lack of appreciation that not all carbohydrates are equal in their health effects.

Beyond this, now there has even been confusion as to whether high fiber diets with whole grains are good for you or bad. This is mostly a result of strong claims made by people with large online followings and promoting specific diets.

What does the best evidence tell us about different carbohydrate types and impacts on health outcomes? Should carbohydrates be viewed as inherently harmful? How solid is the evidence on whole grains, legumes and other high-fiber carbohydrate-rich foods?

To help us tease through the science in this area, in this episode we get some answers from nutrition epidemiologist, Dr. Andrew Reynolds.

About the Guest:

Dr. Andrew Reynolds is a nutrition epidemiologist working with achievable lifestyle and environment change in the prevention and management of non-communicable diseases, such as type 2 diabetes and cardiovascular disease. He primarily conducts randomised controlled trials and meta-analyses. Much of his work is to inform evidence-based dietary or clinical guidelines, policy, and food reformulation.

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“Personalized nutrition” has been promoted as an approach that will improve people’s health by prescribing them specific dietary recommendations based on their own genetic and phenotypic data.

The premise is that given we each respond differently to foods, having general dietary recommendations may be doing many people a disservice. And by using an array of personal data, it is now possible to give unique diets that improve health.

The early and interesting findings of research in this area was met with much fanfare, and indeed, many companies are now offering commercial direct-to-consumer services based on genetic and physiological testing, followed by “personalized” dietary prescription. Such testing may include genetic tests, microbiome testing, glucose monitoring data, and more. This data is then fed into machine learning algorithms to prescribe dietary recommendations.

However, do the marketing claims match the current evidence? Does the “proof” it works that is often cited, actually back up the claims? Do personalized nutrition diets actually lead to improved health outcomes over generic, conventional dietary recommendations? Do personalized nutrition diets lead to better outcomes than standard dietetic/nutrition practice?

To answer these questions, we go through the main studies cited in favor of personalized nutrition being superior to typical dietary advice, and see if they indeed support the claims.

So is personalized nutrition superior to standard dietary advice? Let’s find out…

Note: This is a Premium-exclusive episode, so in order to listen to the full episode you’ll need to subscribe to Sigma Nutrition Premium. However, you can listen to a preview here.

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While it has long been acknowledged that high intakes of saturated fat can increase risk of atherosclerotic cardiovascular disease due to their impact on blood lipids, there are some who question the association between saturated fat and heart disease.

Specifically, they may state that the evidence for this association is weak or non-existent, typically by pointing to some commonly cited studies that show null associations between saturated fat and CVD outcomes.

On this basis, they may conclude that there is no basis to aim to limit saturated fat intake to current recommended levels or that reducing saturated fat intake will not actually improve health outcomes.

In this episode, Alan and Danny look at the four most commonly cited publications showing a null association, highlighting some key issues. Beyond that, they look at a number of other lines of evidence on saturated fat that allows one to come to a confident answer on this question.

So does reducing saturated fat intake to recommended levels actually reduce heart disease risk? Let’s discuss…

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About this Episode:

The beneficial impact of a high-fiber diet is something that has been promoted in nutrition for a long period of time. But there remain a variety of interesting questions to researchers, practitioners and the general public alike.

How much fiber do we actually need? What are current fiber recommendations based on? What outcomes have the strongest evidence for benefit? Should we have targets for fiber sub-types? Are some types of fiber “better” than others? Do functional fibers added to food products still retain the benefits we see with dietary fiber?

To help get to some evidence-based answers on these issues, our guest in this episode is one of the researchers at the forefront of dietary fiber research for decades, Professor Joanne Slavin.

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Description:

Blood glucose responses play a crucial role in maintaining good health, and any abnormalities in glucose regulation can lead to several chronic conditions. Diabetes is one such disease that results from a lack of insulin production or the body’s inability to use insulin effectively, leading to elevated blood glucose levels.

There has been debate about what exactly constitues a “healthy” and “unhealthy” blood glucose response. While it is suggested that unhealthy blood glucose responses are characterized by erratic and unpredictable “spikes” in blood glucose levels, sometimes vague terminology leads to people worrying about normal blood glucose responses. This may be particularly related to the increasing prevalence of continuous glucose monitoring (CGM) devices that allow individuals to track their glucose levels in real-time. While these devices can be helpful for people with diabetes to manage their glucose levels, they can also lead to unnecessary concern and anxiety about small, normal glucose elevations.

In recent years exciting advances have been made in diabetes remission research. And off the back of that, more research has looked at various dietary interventions that could either directly impact remission, or act as an adjuct to other interventions.

In this discussion with Dr. Nicola Guess, we discuss a range of topics related to glycemia, diabetes, and diet. This includes the potential for high-protein interventions, what utility CGMs actually have, what to make of diabetes remission trials, and future directions for the field.

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Description:

Understanding the concept of an “exposure” is a critical aspect to nutrition science literacy. The ‘exposure of interest’ refers to the variable or factor that is being studied to determine its relationship with a particular health outcome.

For example, in a study examining the relationship between diet and heart disease, the exposure of interest may be a particular nutrient or food group, such as saturated fat or red meat consumption.

But when reading research we need to be able to critically examine the levels of an exposure and ask were these suitable for the research question at hand.

For example, is there a sufficiently wide contrast in the exposure between the groups being compared? How do the reported levels of intake relate to what we know about this exposure from the wider literature?

Much has been made of the many ’null’ associations found in nutrition epidemiology. But in many cases, these may be accounted for by looking at the exposure contrast or absolute intakes in those studies. Something we referred to as “null by design”.

In this episode, Danny and Alan go through the most crucial aspects to understand about the exposure of interest in nutrition, hopefully leading to an enhanced understanding of interpreting nutrition research.

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Description:

Substantial evidence shows that a high intake of saturated fat in the diet has the potential to significantly raise LDL-C and ApoB-containing lipoproteins in many people, and in turn increase their risk of developing atherosclerotic cardiovascular disease (ASCVD).

However, people may raise what seems to some contradictory evidence, or what is sometimes thought of as a paradox: the impact of full-fat dairy on CVD risk.

This paradox arises because given the saturated fat content of full-fat milk, yogurt and cheese, we typically don’t see the same impact on blood lipid profiles. In addition, epidemiology can often show such foods in a favourable light. And the dairy fat story gets more interesting when we look at evidence showing there is a huge difference in the impact of consuming different dairy foods (e.g. butter vs cheese/yogurt).

So this leads to many questions that people rightly ask, which we aim to address in this episode. Questions such as:

• Why doesn’t increased dairy consumption lead to same increases in CVD risk as other saturated fat sources?
• Do results from full-fat dairy studies prove that saturated fat isn’t a problem?
• What is it about cheese/yogurt that makes it different to butter?
• How do low-fat and full-fat dairy compare?
• Diets including/excluding dairy: how to compare?

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Introduction:

Discordance between low-density lipoprotein particle (LDL-p) and low-density lipoprotein cholesterol (LDL-C) occurs when the levels of these two biomarkers do not match up as expected. Discordance between Apolipoprotein B (ApoB) and low-density lipoprotein cholesterol (LDL-C) is similar, except rather than counting just LDL particles, ApoB is a measure of the numbers of lipoproteins that have an ApoB attached.

Discordance between ApoB and LDL-C can lead to either an underestimate or overestimate of ASCVD risk. And therefore there may be important implications for someone who does have discordance. Additionally, it is such cases that suggest that a measurement of ApoB may provide additional information beyond traditional lipid measures in assessing a person’s cardiovascular risk.

Recent work from researchers at Liverpool John Moores University has investigated whether discordance is associated with certain dietary patterns.

In this episode, one of the researchers involved, Dr. Ian Davies, is on the podcast to discuss this work in addition to wider questions in the diet-lipids-CVD field that remain to be answered.

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Description:

Fructose is a type of sugar that is commonly found in fruits, vegetables, and many processed foods. In recent years, there has been a lot of discussion and debate about the impact of fructose on health, with some claiming that it is a major contributor to obesity, diabetes, and other chronic diseases. However, these claims are often at odds with what the scientific literature actually says.

One of the most common claims about fructose is that it is inherently “bad” for health, and that consuming too much of it can lead to a wide range of health problems. This idea has been popularized in many popular diet and health books, and has led to a widespread fear of fructose among the general public. However, many of these claims are based on outdated or oversimplified research, and do not reflect the complex reality of how fructose interacts with the human body.

Another common claim about fructose is that it is uniquely responsible for the current obesity epidemic, and that reducing fructose intake is the key to weight loss and better health. While it is true that excessive consumption of sugary foods and beverages can contribute to weight gain and other health problems, the idea that fructose is uniquely responsible for these issues is not supported by the scientific evidence. In fact, many studies have found that total sugar intake, rather than fructose specifically, is the most important factor in the development of obesity and related health problems.

In this episode we discuss the unique aspects of fructose metabolism, why some studies appear to show unique harm of fructose, and the implications of this for dietary choices.

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Description:

The idea of food addiction has gained a lot of attention in recent years, as obesity rates continue to rise around the world. Many people struggle with overeating and find it difficult to resist certain foods, leading to a cycle of guilt and shame. The concept of food addiction suggests that there may be a biological explanation for this behavior, and that certain foods may be especially “rewarding” to the brain, leading to a kind of addiction.

To help look at the evidence in this area, our guest in this episode is Dr. Charlotte Hardman, who is a leading researcher in the field of appetite and obesity. Dr. Hardman’s research focuses on the psychological and biological processes that contribute to overeating and obesity. She is particularly interested in the concept of “food addiction,” which suggests that certain foods may be addictive and lead to compulsive overeating, similar to substance addiction.

In this podcast, we will explore the latest research on food addiction with Dr. Hardman. We will delve into the evidence for and against the idea of food addiction, as well as discuss the potential implications for public health and policy. Join us as we explore this fascinating topic and learn more about the complex relationship between food and the brain.

• [00:03:01] Mechanisms that keeps weight stable over time?
• [00:11:52] Semaglutide: Game-changer? Weight regain?
• [00:30:42] How to further lower LDL-C? Can I avoid statins?
• [00:43:52] Glyphosate: A cause for concern in food?
• [00:48:30] High caffeine intake is making me sweat more. What’s going on?
• [00:55:16] Should I avoid non-organic meat?
• [01:00:08] Is there evidence on iron and zinc co-ingestion for anemia of prematurity?
• [01:03:09] “Carni-nutrients”: Can vegan diets cause brain issues due to lower choline, creatine and taurine?
• [01:12:10] Are energy drinks bad for us?
• [01:17:43] What are some resources for doctors and patients that simply explain obesity & treatments?

This is an episode exclusive to Premium subscribers. To listen to the full episode you’ll need to subscribe. However, you can listen to a preview here.

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Often claims are made recommending that people should aim to keep peaks in blood glucose low in terms of both magnitude and frequency.

And while many claims about blood glucose “spikes” are incorrect or purposefully exaggerated to grab attention, there are some reasonable and interesting hypotheses put forward in relation to blood glucose variability and excursions.

For example, interesting questions have been raised in relation to the impact of blood glucose excursions in seemingly normoglycemic and/or healthy people.

In this episode, we look at three specific elements of this: average blood glucose, glucose variability, and glucose peaks. All in the context of people without prediabetes or type diabetes, who have typical blood glucose measures in the ‘normal’ range.

Specifically, we look at three hypothesized recommendations made elsewhere:

1. “The lower you average blood glucose (HbA1C) is better, even if already in normal range”
2. “The more you can minimize glucose variability, the better.”
3. “Minimizing the number of glucose “peaks” is important, even if they don’t meet the threshold for hyperglycemia”

Can normoglycemic people benefit from further reducing these measures? Let’s take a look…

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Depression is a common disorder and is a leading cause of disability worldwide. Depression results from a complex interaction of social, psychological, and biological factors.

Diet has been one area that has been suggested in playing a role; from potential for exacerbating symptoms to being a treatment. And while some associations have been noted, many claims far exceed what (little) evidence exists.

Online it is common to see people claiming certain diets can treat depression or that certain foods will improve outcomes. However, does the evidence match such claims?

In trials that have been published on diet-depression, there has been considerable media attention and fanfare around some results. For example, the SMILES trial published out of Australia. However, some have raised considerable concerns about the interpretation of such findings.

In this episode, clinical psychologist Dr. Nicole Lippman-Barile is on the podcast to discuss what we currently know about diet and depression, what issues exist with current studies, and why many nutrition-mental health studies are being incorrently interpreted.

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Description:

When thinking about the effect of eating or not eating a certain food or nutrient, we can’t consider this in isolation. Meaning, we need to evaluate the impact within the context of what such an inclusion/exclusion does to an individual’s overall diet pattern.

Thinking about this concept, the phrase “compared to what?” has been colloquially used. And while this is an important idea, there has been some misapplication of this principle.

In nutrition science, this is related to the concept of food or nutrient “substitution”. And this concept is crucial to understanding the issues that can arise in nutrition studies, particularly when it comes to single food analyses in nutritional epidemiology.

This concept of substitution is quite intuitive in controlled feeding studies. However, it is not as obvious when considering nutrition epidemiology studies. As noted by Ibsen & Dahm (2022):

“Whereas studying the effects of eating one food instead of another is typically explicit in interventional study designs, it is often implicit and sometimes hidden in analyses of observational studies.”

However, in nutrition epidemiology substitution is still happening, but it typically emerges as a consequence of adjustment models. In nutritional epidemiology, it is essential to adjust for confounders. E.g., one vital adjustment is often for total calorie intake. However, when our exposure is a specific food/nutrient, we must think about confounding by other foods.

So knowing what, and how, a study is adjusting for variables helps us interpret it better.

In this episode, Dr. Alan Flanagan and Danny Lennon discuss these crucial ideas of food substitution, adjustment models, and “compared to what?”.

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About This Episode:

Does sodium lead to calcium losses? Do high-salt diets harm bone health? At what thresholds could there be an impact? Does any of this change our recommendations around salt/sodium intake?

Thanks to Sigma Nutrition Premium subscriber Kate Wall for submitting a question in the member’s area that inspired this episode.

Kate asks: “Salt can impact calcium excretion in the urine and it is said that a high salt diet can increase risk of osteoporosis as it draws calcium from the bone and excretes it. How much of an impact does dietary salt intake actually have on bone health and how high would salt intake have to be for this to be a concern? Obviously high salt intakes are not something to aim for in general, but just wondered if this was a mechanism that could remove meaningful amounts of calcium in a way that I should be advising around this in those that we work with as nutritional professionals. Thanks!”

So in this episode, Danny and Alan look at some of the evidence in this area to see if there are impacts that have pragmatic implications for nutrition and medical professionals, as well as health-concious people.

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Description:

Nutritionists, dietitians and other health & fitness professionals face many challenges when attempting to help their clients and in understanding what approaches are best in a given situations.

There are often discussions around improving client adherence to dietary recommendations. However, sometimes we need to think deeper about this topic. Is there really just a tool to fix this? Or could the problem be the recommendations themselves?

Similarly, while quantifying dietary intake in terms of calorie and macronutrient amounts can be useful in some cases, it’s clear that this isn’t the best approach in many cases. So for coaches aiming to help athletes or those with body composition goals, how do we use “non-tracking” approaches effectively?

This episode brings you a roundtable discusssion between three accomplised and insightful nutrition professionals; Dr. Eric Helms, Dr. Zoya Huschtscha, and Mackenzie Baker. In the episode we discuss the above-mentioned topics and more.

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Research in the field of ‘chrononutrition’ has continued to grow in the past couple of years, with some important studies being published in recent times. Chrononutrition is a research area that looks at the relationship between temporal (time-related) eating patterns, circadian rhythms, and metabolic health.

While past podcast episodes have covered various aspects of chrononutrition, the latest research has added important pieces to the puzzle and has lead to both Alan and Danny updated their views on certain sub-topics.

In this episode, we look at recent research (including that from the Big Breakfast Project) and how understanding and conclusions from the field have shifted over time. Dr. Flanagan also gives some insight into the important chrono work published in the UK, which his dotoral work contributed to.

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There is almost universal agreement that excess added sugar in the diet is detrimental to health. However, much of this negative health impact clearly relates to the ability of high sugar intakes to drive excess calorie intake and fat accumulation, which cause health issues.

But what about situtaions of where there is not a calorie surplus (hypercaloric diet) or weight gain?

Some people claim that sugar is inherently damaging. While others push back and claim sugar is only a problem in the context of a hypercaloric diet. So which position is more accurate? What evidence do we have?

In this episode, Dr. Alan Flanagan and Danny Lennon take a look at situations of eucaloric (or even hypocaloric) diets, and what impact sugar has. Specifically, they investigate: in a situation where someone is not overconsuming calories or gaining weight, what health impacts do added sugars have? And if there are these calorie-independent effects, at what thresholds do they occur?

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This episode brings you a “debate” between Danny Lennon and Dr. Jackson Peos on the utility of intuitive eating. Specifcally, they make a case for and against, respectively, for the position: “Intuitive eating can be recommended eating approach for those with fitness and/or physique goals”.

This episode is a Premium-exclusive episode, so you’ll need to be a Premium subscriber to listen to the full discussion but you can hear a preview here.

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Iron deficiency is a prevalent issue. Worldwide, it is the leading nutritional deficiency. And although there is lower prevalence in high-income countries, a significant number of people are still affected.

Iron deficiency may be a result of too little iron coming in (i.e., via diet choices or low absorption), or from excess losses (e.g., commonly from blood losses). Understanding how these can impact iron status is crucial for both accurate diagnosis and treatment.

In relation to dietary iron, the source of iron is a common talking point, as there are two forms of iron that we can consume. Heme iron is found in meat, fish, and poultry, while non-heme iron is found in plant foods. It is known that heme iron is more readily absorbed than non-heme iron. However, there is much more to this story that makes things complicated.

To discuss some of the nuances of iron bioavailability, absorption, and metabolism, leading expert in the area Professor Paul Sharp of King’s College London is on the podcast. Prof. Sharp discusses crucial aspects of dietary iron sources, bioavailability, supplementation, and impacts in the body.

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Iron is involved in a whole range of biological processes and a consistent supply of iron is crucial for cellular turnover. But despite iron being an essential mineral for human function, it is highly toxic to cells and tissues if present at high levels. Therefore an intricate and tight regulation of iron is necessary.

If iron status gets too low, iron-deficiency anaemia can result. In such situations there is a shortfall in hemoglobin production, which leads to a range of issues in the body.

So how is iron status measured? Which biomarkers are most useful? Where can errors in diagnosis occur? What problems arise with iron deficiency? And what problems occur with iron overload?

In this episode, these questions (and more) are put to Dr. Austin Baraki, a practicing Internal Medicine physician and Assistant Professor of Medicine at William Beaumont Army Medical Center in Texas.

This episode is the first in a three-part series on iron.

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In October 2022, Ruddick-Collins et al. published results of an RCT looking at the impact of different calorie distributions across the day. This study was from the ‘Big Breakfast Study’ project, primarily from the University of Aberdeen.

In this study, 30 subjects underwent two 4-week calorie-restricted diets that were matched for calories. One diet was “morning-loaded”, meaning that daily calories were distributed as 45% at breakfast, 35% at lunch, and 20% at dinner. The other was “evening-loaded”, with an opposing calorie distribution; i.e., 20% at breakfast, 35% at lunch, and 45% at dinner.

The trial received a lot of commentaries online after it was published. However, much of it lacked sufficient context, nuance, and understanding of the implications.

In this episode, Dr. Alan Flanagan, who was one of the researchers involved in some of the work of the Big Breakfast Study, gives an insight into the recently published paper by Ruddick-Collins et al., and highlights some important aspects to be aware of.

This is an episode exclusive to Sigma Nutrition Premium subscribers.

To listen to the full episode and access the transcript, you must subscribe to Sigma Nutrition Premium.

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In this episode, the Sigma team explores the question: “Do vegan diets increase the risk of depression?”

This is a question that emerges from a few different places. First, it’s common to hear such a claim from proponents of largely animal-based diets. Some reference is often made about how vegan diets can, at best, worsen symptoms or, at worst, even cause depression. Or conversely, they may state that moving away from a plant-based diet will improve mental health outcomes, including depression.

And while all of those specific claims aren’t within the scope of this episode, such claims do get people wondering if a plant-exclusive diet is actually a cause of various mental health ailments.

But is there a basis for such claims?

In this episode, we explore the evidence from two ends: 1) research related to the proposed mechanisms by which a vegan diet could cause problems, and 2) outcome data looking at the impact of such diets.

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About this episode:

Over the past decade, the increasing uptake and acceptance of the Nova food processing classification system has placed focus on one of the categories in Nova; ultra-processed foods (UPFs). Ultra-processed foods (UPFs) are products created from deconstructed (and recombined) food components, usually with the goal of creating a highly palatable, convenient, and profitable product. This typically means such products are high in nutrients of content (e.g. sugar, sodium, saturated fat, etc.). But in addition, they have other characteristics that may make them detrimental to health, particularly when they replace unprocessed or minimally processed foods in the diet.

There is now clear evidence showing that when such products make up a large proportion of the diet, such a dietary pattern has negative health effects. However, there are still many unanswered questions and many debates within nutrition science about how to best classify UPFs, to what degree they need to be limited, whether some can be beneficial, and what to do with policy going forward.

To offer one perspective on this issue, Associate Professor of Food Politics and Policy at the University of Melbourne, Dr. Gyorgy Scrinis, is on the podcast to discuss his work in the area.

While we have discussed the problem of reductionism in nutrition science previously on the podcast, Dr. Scrinis’ use of the term ‘reductionism’ does differ a bit from the way others use the term. For example, he suggests that nutrition science has been too reductive even at the food-level and dietary-pattern level.

His work on ultra-processed foods and the Nova classification system has attempted to understand the technological and corporate character of ultra-processed foods, the power of food corporations, and how food corporations shape and capture nutrition science for the purposes of promoting and defending their products.

Research has shown that food marketing strongly impacts children’s eating behaviour. Marketing influences food purchase requests, purchases, and preferences.

And the evidence of a relationship between food marketing exposure and obesity meets epidemiological criteria for causality. The evidence suggests that the impact of food marketing is a function of both exposure to the marketing message and its persuasive power.

What does the current evidence tell us about the exact effect of marketing on food choices? And beyond that, what strategies are likely to yield the best results in terms of mitigating the harms of food marketing on eating behaviour, particularly in children and adolescents?

To help answer these questions, subject area expert Prof. Emma Boyland is on the podcast to discuss what is currently known.

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Never before has there been greater access to information about nutrition and health. But never before has there been such a low barrier to being seen as an “expert”. There are large numbers of people getting information from, and basing their health decisions on, people who don’t have direct expertise in the field in which they are talking about.

Moreover, some promote the lack of domain expertise as a feature, not a bug. They claim that those that were conventionally seen as domain experts are either brainwashed, lazy in their thinking, or outright corrupt. And the solution is instead to look to those with a fresh perspective that can illuminate us on the “truth”.

In this episode, Alan and Danny discuss this “death of domain expertise”, how it plays out online, and its ramifications for people’s ability to get good information.

This is a Premium-exclusive episode. To listen to the full episode and access the transcript, you must subscribe to Sigma Nutrition Premium.

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Obesity increases the risk of a range of chronic diseases and negative health outcomes. And trials where a sufficient amount of weight loss is achieved show health improvements. However, despite the “straightforward” nature of causing weight loss through a hypocaloric diet, it is clear that most people who lose weight will regain some or all of the weight.

This is a result of both the physiologic control of intake and expenditure (i.e. homeostatic regulation by the body to avoid staying at a lower body or fat mass), and environmental factors. Diet-induced weight loss is followed by a number of hormonal change that encourage weight regain. So how do we tackle this problem?

In this episode, Dr. Priya Sumithran discusses this physiologic control of body mass, in addition to environmental and behavioural factors that make weight loss maintenance difficult. Dr. Sumithran also discusses what this means for setting weight loss targets, choosing the correct intervention, and looking to non-weight-centric approaches for certain individuals. We also discuss the evidence on GLP-1 receptor agonist drugs, such as Semaglutide, as a treatment for obesity.

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The endocrine system plays a central role in growth, development, metabolism, reproduction, and physical well-being throughout life. Hormones interact in complex networks, orchestrating a range of critical functions. Over the life course, we experience various changes in hormone levels, fluctuations, patterns, and actions. Additionally, lifestyle factors and disease processes can impact the levels and functions of hormones.

In this episode, Dr. Nicky Keay, a medical doctor with expertise in the field of exercise endocrinology, is on the podcast to discuss a variety of endocrine-related issues, including: hormone diurnal variation, bone health, amenorrhoea, HRT, perimenopause, and thinking about hormones and aging.

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Stable isotopes have been used as tracers in human nutritional studies for many years. But what are they? Why do we use ‘tracers’ in nutrition studies? And what are some practical examples?

A chemical element can have different forms or ‘isotopes.’ These different isotopes have the same atomic number and position in the periodic table but have different atomic masses and physical properties. An isotope that is not radioactive is said to be ‘stable’.

In physiology and metabolism research, stable isotopes are used as ‘tracers.’ As the name implies, it allows us to ‘trace’ the fate of compounds, thus giving a very detailed insight into the metabolism of nutrients and the regulation of many disease processes.

In this episode, Dr. Alan Flanagan explains what stable isotope tracers are, how they are used to answer nutrition science questions and some examples that you may come across.

This is a ‘Nutrition Science Explained’ episode. These episodes are exclusive to Sigma Nutrition Premium. To listen to the full episode and access the transcript, you must subscribe to Sigma Nutrition Premium.

Given the negative consequences of consistent overconsumption of food (leading to a caloric surplus), having a dietary intake that is of appropriate calorie intake is an important aspect of long-term health. Therefore, thinking about which foods and diets can help promote appropriate satiety to keep calorie intake in check is a key focus for many researchers and practitioners.

There is a complex system of human appetite control. This appetite system influences food consumption and associated motivational drives such as hunger, as well as interacting with and being influenced by energy expenditure. Satiety is an important psycho-biological process involved in the expression of human appetite, inhibiting hunger and intake following food or beverage consumption.

In this episode, the Sigma team discusses the human appetite system, how different nutrients and foods impact satiety, and the implications of this research.

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Exercise improves metabolic control both via increasing muscle glucose uptake during muscle contractions by insulin-independent mechanisms and by increasing skeletal muscle insulin sensitivity after physical activity. A reduction in skeletal muscle insulin sensitivity is an early event in the development of not only prediabetes, metabolic syndrome, and type 2 diabetes but is also associated with other conditions such as cardiovascular disease and some cancers.

One of the researchers that has been at the forefront of research in this area for many years is Professor Glenn McConell. In this episode we discuss glucose uptake during and after exercise, looking at both insulin-dependent and insulin-independent mechanisms. In addition we discuss the crucial importance of muscle insulin sensitivity and some important research breakthroughs on the topic.

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The term ‘tactical populations’ has been applied to those working in law enforcement, fire, first responders, and military. In addition to the importance of their work, the work they do itself presents some challenges for health and nutrition.

Despite the fact that such individuals make up a significant number of the population and their work plays a crucial role in society, there is currently very little research on fire and law enforcement nutrition. Most research is on the prevalence of disease and the occupational risk factors and related pathophysiology. Lifestyle research, descriptive and interventions, is way behind.

Dr. Jill Joyce is the co-director of the OSU Tactical Fitness and Nutrition Lab at Oklahoma State University. She does research looking at real-world interventions in these populations, particularly firefighters, in an attempt to improve their diets and health.

In this episode, we look at both the theoretical and pragmatic realities of improving diet and health in firefighters and some other tactical populations.

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• Live Event: Berlin, Germany on November 26th 2022
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When it comes to eating to promote muscle hypertrophy, muscle repair/recovery and maintenance of mass and function, protein has been an obvious focus. Indeed muscle mass and quality are dependent on the continuous remodeling of skeletal muscle proteins. This is related to the amount of muscle protein balance, i.e. the net difference between muscle protein synthesis (MPS) and muscle protein breakdown (MPB). Because of this, MPS has long been used as a proxy measure for muscle repair and/or growth of muscle.

Protein feeding increases MPS, with the amino acid leucine having a specifically strong impact on MPS. Therefore both the dose of protein and the amino acid profile of the protein have been looked at to assess which protein sources are “superior” for muscle mass and function. This has typically led to viewing animal proteins as better than plant proteins.

But many assumptions are layered into conversations on the topic. In this episode we explore some important points that are often neglected. Is MPS as reliable as we assume? Does the amino acid profile tell us everything about the anabolic effect of a protein? Does dose and timing matter as much as we think? How does the picture change when we look at whole foods or mixed meals?

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• Live Event: Berlin, Germany
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The brain plays a central role in both physical and psychological function and performance. The brain also has a very high energy demand. In addition, fatiguing conditions can cause impairment of cognitive performance.

One area of research in neurometabolism related to the potential use of nutrients on improving cognitive function, as well as “rescuing” the fatigue-related declines in performance.

Nick Gant is Director of the Exercise Neurometabolism Laboratory at the University of Auckland. His group uses interdisciplinary approaches from the nutritional sciences and neurosciences to investigate the role of nutrition in brain health and performance. Nick is particularly interested in foods and supplements that prevent brain fatigue and improve physical and cognitive function.

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This episode was oringally published as one of our “Expert – ask me anything” (AMA) episodes, which we published for Premium prescribers. In such bonus episodes, we collect questions from Premium subscribers and ask them direct to a world-class expert and past podcast guest.

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In this episode Prof. Stu Phillips takes questions about synethized whey protein, plant proteins, post-exercise MPS, and many other topics related to protein, muscle function and ageing.

It has been consistently shown in research that elevated dietary sodium consumption is associated with high blood pressure and an increased risk of cardiovascular disease. In addition, low levels of dietary potassium intake are associated with these same risks. However, there is some debate on how to characterize these relationships.

In a study published in European Heart Journal in July 2022, using data from the EPIC-Norfolk study, researchers attempted to answer whether the associations between potassium and both blood pressure and cardiovascular disease: 1) differ between men and women? and 2) depend on daily sodium intake.

In this episode Dr. Alan Flanagan and Danny Lennon discuss the details of this study and then link it to the overall evidence base and what this may mean for potassium (and sodium) intake considerations.

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A study published in March 2022 suggested that consumption of artificial (non-nutritive) sweeteners is associated with a 13% increase in risk of cancer.

And so in this episode, Dr. Alan Flanagan, Dr. Niamh Aspell, and Danny Lennon discuss this specific study and give their thoughts on what are fair conclusions to come to.

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While we’ve never known more about diet and health, there remain many unanswered questions in nutrition science. However, there is often disagreements on how best to answer these questions, particularly in relation to informing practical diet advise that meaningfully improves health.

Prof. Norman Temple is one academic who has written on a number of these issues. One issue he highlights is the large discrepency in the practical value we have attained from cohort studies and RCTs, relative to mechanistic research. Another is the limitations of RCTs for nutrition-specific research questions.

In this episode, Prof. Temple discusses these issues, as well as what strategies can actually improve population diet, and thus health.

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A recent study reported a higher risk of developing melanoma in people who ate a relatively high intake of fish. This study caused headlines and it was picked up by many outlets (including the New York Times, Sky News, etc.).

In this episode, Alan and Danny dig into the nuances of this study to see if the headlines are justified.

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This is an “ask me anything” (AMA) episode, which means a world-class expert and past podcast guest comes on the podcast to answer questions submitted by you, our podcast listeners.

Stephan Guyenet spent 12 years in academia studying neurodegenerative disease and obesity neuroscience. He was a postdoctoral fellow at the Univeristy of Washington, studying the neuroscience of obesity and eating behavior. Previous to that he completed a PhD in neuroscience.

Stephan is the author of the popular and well-received book ‘The Hungry Brain‘, which lays out the science behind the brain’s role in obesity.

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1. “When someone undergoes liposuction or other surgery that removes adipose tissue, is there a sudden reduction in leptin levels? While this may reduce leptin resistance, could the drop in leptin lead to increased hunger over time?”
2. “What is the current research around how chronic energy restriction (or following crash diets) affects appetite hormones and/ or appetite regulation long term? Is there a physiological mechanism influencing overeating attributable to appetite dysregulation caused by chronic dieting? I ask as this is something I am often tackling in my nutrition consultancy but research in biochemical and physiological mechanisms seems lacking.”
3. “Can you talk about the conditions of anorexia and morbid obesity and how they essentially defy the rules of metabolic compensation? In other words- I understand anorexia to be a mental health condition where the individual starves themselves with a purpose to control weight. And morbid obesity being excessive consumption despite over fatness, etc. If the body has these numerous mechanisms by which calorie restriction or calorie over- consumption results in these compensatory processes-driving us to eat more/less slow us down/speed us up, and many more; do these individuals not “hear” these signals or are they just adept at ignoring them or is it that their bodies have lost the ability to compensate for their under or over consumption? Additionally, can anyone become anorexic or morbidly obese? Or is it merely genetics?”
4. “Why do some SDRIs (serotonin–dopamine reuptake inhibitors) and serotonin precursors reduce hunger/appetite? E.g. 5-HTP and Wellbutrin (Bupropion)”
5. “Question about the ideal weight program: As an iOS developer, my instinct is to assume determinism and quantifiability of the entire universe. I believe this to be fundamentally true. But what is hypothetically possible differs from what we can realistically know. I worry that attempts like yours to quantify some seemingly qualitative measures are doomed. I have similar concerns about happiness research. How do you reassure yourself you can really construct an algorithm that deciphers the “ideal weight program” for any given user – do you rely on averages?” a. Quick explanation of the ideal weight program
6. “In 2018 a poster was presented at the annual meeting of the Society for Neuroscience titled ‘The human brain microbiome; there are bacteria in our brains!’ which showed bacteria apparently penetrating and inhabiting the cells of healthy human brains. While the work was preliminary, have you heard of any further work in this area? What is your opinion on the possibility that, if bacteria do inhabit the brain, they could play a part in appetite regulation and/or obesity similar to how the gut microbiome can affect our health?”
7. “It seems like there are significant differences in policies put forth between researchers from biomedical backgrounds and ones from public health policy backgrounds. Dr [David] Allison touched on this during recent interviews, noting that there is very little evidence regarding the efficacy of upstream obesity prevention interventions, such community gardens, combatting food deserts, nutrition education, and cooking classes. On the other hand, governments are increasingly turning to such interventions, as well as policies such as front of pack labelling (Canada, 2022), nutrition facts tables, calorie labelling on menus, as well as the aforementioned ones. Given your research on determinants of health and obesity, what are some of the most promising interventions to prevent NCD morbidity, as well as stones unturned in public health policy? Would you agree with individuals such as Dr Allison that in our current environment, the only efficacious interventions are drugs and bariatric surgery?”
8. Question based on your debate on JRE with Gary Taubes: “Would the insulinogenic effect of protein, specifically something like whey protein which causes an insulin response, be something that should automatically refute Taubes arguments about insulins inherent role in increasing adiposity? Second, would overeating on any macronutrient increase insulin simply because you are eating more food (i.e. hypercaloric)?”
9. “Are there best practices for the maximum duration someone should spend in fat loss (or weight gain) phases? Or perhaps an optimal ratio of fat loss phase duration to “maintenance” phase duration? For example, should fat loss phases be for a maximum of 12 weeks followed by maintenance of at least equal duration before resuming a fat loss phase?
10. “I’m a naturally skinny guy who helps other naturally skinny guys bulk up. I think it largely comes down to a blunted pleasure response to food, smaller stomachs, and/or higher NEAT. A lot of us seem to be taller and more thinly built, too. But why do you think things are things so different for us? Why is it so hard to gain weight? And what can we do about it?”

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Climate change refers to long-term shifts in temperatures and weather patterns. These shifts may be natural, such as through variations in the solar cycle. But since the 1800’s, human activities have been the main driver of climate change, primarily due to burning fossil fuels like coal, oil and gas.

Climate change has the potential to negatively impact the nutrient value of plants, soil organisms, food stuffs, via a variety of ways. Climate change puts food supplies at risk. Floods, droughts, more intense hurricanes, heatwaves and wildfires can drive down crop yields, destroy livestock, and interfere with the transport of food. And rising carbon dioxide levels from human activity can make staple crops like rice and wheat less nutritious.

In this podcast the Sigma team take a look at the evidence on how climate change will impact nutrient status, if left unchecked. There will be also a look at what solutions have been put forward to tackle this issue. This episode will focus more on how climate change impacts nutritional & nutrient status, as opposed to converse (but equally important) issue of how food systems impact climate change.

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When it comes to specific questions related to diet and health for women, there is often a shortage of consensus answers from research, for a variety of reasons. In addition, there are clearly aspects of biological sex that have implications for health and also the interaction with diet. For example, the impact of the menstural cycle, of menopause, and differences in nutrient requirements.

In this episode, Dr. Hazel Wallace discusses some of these key considerations. Some things covered include: the impact of menstrual cycle phase on cravings, at-risk nutrients in pre-menopausal women, functional hypothalamic amenorrhea, interaction of diet and PMS, the physiological changes at menopause and potential role of diet.

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This is a preview of the second episode in a new series called “Nutrition Science Explained”, in which members of the Sigma team will take a concept commonly mentioned in discussions about nutrition science, and explain what it is, give more background context, and highlight important aspects to know. The goal is to aid listeners to have a deeper understanding of other episodes when such concepts are mentioned.

In this episode Alan Flanagan discusses the concept of the GRADE system, and specifially how it applies to evaluating nutrition research and coming to conclusions for practice.

GRADE (Grading of Recommendations, Assessment, Development and Evaluations) is a framework for developing and presenting summaries of evidence and provides a systematic approach for grading the quality of evidence and making clinical practice recommendations.

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Folate (also known as viatmin B9) actually relates to a collection of folates; both natural dietary folates and synthetic forms, primarily folic acid. This folate/folic acid that is consumed via the diet or supplementation is a precursor for the formation of tetrahydrofolate (THF), which is a carbon donor and acts a cofactor for a number of enzymes that play important roles in several processes. In this episode, Alan and Danny discuss the role of folate in the methlyation cycle, the impact of folate insufficiency/deficiency, genetics variatnts of the MTHFR gene (and other genes) that impact folate metabolism, and the impact of folate on health outcomes; including heart disease, birth defects, cancer, and brain health & cognition. Detailed study notes and transcript to this episode

• What is the connection between choline and DHA? What is the PEMT pathway?
• Study design for the choline + DHA trial
• Are there risks of high-dose choline?
• Main findings of the trial
• How DHA status is not just a function of DHA intake, but also methyl metabolism too
• Issues with omega-3 trials; e.g. not taking baseline status into account
• Pragmatic recommendations for health professionals and patients
• Different forms of choline supplements
• Choline supplementation vs. food-derived choline

In this episode Alan and Danny aim to address the idea that you shouldn’t eat vegetables, or that they aren’t beneficial. We will specifically look at a number of claims that relate to:

1. The claim that vegetables aren’t beneficial for health, or that there is no health benefit to high vegetable intake.
2. The claim that vegetables are actually detrimental to health, and their removal improves health.

This episode was orignally published to Sigma Nutrition Premium. If you wish to get more of these Quack Asylum episodes (and lots of other features, including detailed study notes) then subscribe to Sigma Nutrition Premium.

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This is an "ask me anything" (AMA) episode, with Prof. Stuart Phillips of McMaster University. Prof. Phillips takes questions on protein intake, sources, muscle function, and healthy ageing.

To listen to the full AMA, click here to subscribe to Sigma Nutrition Premium.

Questions answered:

• [04.28] What is muscle protein balance?
• [05.32] Why is the focus always on muscle protein synthesis?
• [07.14] Is MPS a good proxy measure for outcomes we care about (e.g. muscle growth/repair)?
• [10.37] What's the difference between 'whole body protein synthesis' and 'muscle protein synthesis'?
• [12.57] We're starting to see commercially available whey that has been produced by bacteria engineered to synthesize whey protein directly from nutritional substrate. It seems like we should expect this to have directly comparable effects given the identical molecular structure. Is there any reason to think this bacterially synthesized whey will have any different effects that whey from dairy?
• [15.50] Does the literature still show that an additional dose of plant-derived protein is required to equate a similar response from animal protein?
• [26.39] During post-exercise conditions does protein ingestion stimulate MPS for longer than the usual 2-3 hour period reported in rested conditions?
• [27.49] Considering the growing interest in fasting protocols (both TRF and longer fasting protocols) - what would you recommend in these circumstances for the preservation / growth of muscle mass. Would it differ between IF/TRF and longer (1-3 day) fasts?
• [34.58] Is it a waste to take too much protein powder at once because some of it won't get absorbed?
• [42.50] Does protein powder lose some of its quality if boiling water is added due to protein denaturation?
• [47.05] Would you please share your opinion about how you evaluate protein status in the body?
• [50.51] I am now over 60 and lift heavy twice a week. What would be a reasonable body fat % for me to aspire to and how much daily protein should I be targetting in my diet?

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Consuming a healthy diet during pregnancy is an obvious and accepted recommedation. However, what exactly is a "healthy diet" in this context? In addition, there are specific nutrients which are crucial for the healthy development of the child, including nutrients which may be difficult to consume enough of. In addition there are nutrients and foods that need to limited or avoided during this period. In this episode, researcher and dietitian Dr. Julie Abayomi discusses important nutrients in pregnancy (e.g. iodine, DHA, and folic acid), as well as potentially problematic nutrients/foods (e.g. high-mercury fish and caffeine). In addition, she discusses the current debates about weight gain/loss during pregnancy, as well as what supports are needed for health professionals supporting pregnant women. Click here for show notes

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It has become common rhetoric for those promoting various types of diets to suggest that dietary guidelines published by government departments are at best, unhealthy, or at worst, causative in driving obesity and chronic disease in the population.

While different countries and organizations produce their own guidelines, with slight differences, most of the conversation has focused on the Dietary Guidelines for Americans, that are created by the USDA.

Often the claims is that following these guidelines actually harms health, rather than promote it. And the guidelines are simply a result of industry forces, long-standing bias, and shoddy science.

But do these claims hold up to scrutiny? In this episode Alan and Danny look at some of the arguments put foward, and take a look at the science underpinning dietary guidelines in a number of countries.

In this episode:

• [0.01.46] Examples of arguments put forward stating that it’s not healthy to follow dietary guidelines
• [0.12.50] History of the development of guidelines in the US & narratives around Ancel Keys
• [0.23.50] Misrepresentation of what the guidelines say
• [0.30.49] What are actually in the current Dietary Guidelines for Americans?
• [0.33.10] Changes to guidelines over time
• [0.36.05] Other countries’ guidelines: UK, Canada, Nordic countries
• [0.40.50] Investigating the rise in obesity/disease prevalence with the roll out of the guidelines
• [0.56.34] Do people follow the guidelines?
• [1.00.01] The negative role of the food industry
• [1.03.50] Potential issues with dietary guidelines

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There have been many claims made about the benefits of a detoxification "protocol" or "plan", based on specific dietary and supplemental regimens. Many of the arguments propose that many things we come into contact with are toxins and they can accumulate and compound in effect over time, causing a range of issues. Therefore, by removing these toxins (via a “detoxification protocol”), we can have better health.

And indeed it is well known that there are a large number of toxins in the environment, many of which can potentially be deleterious to health. And it also known that many nutrients are involed in processes of the body's detoxification pathways.

However, is there any evidence that a detoxification diet, plan or "protocol" improves health? Is there any reason to suggest targeting certain nutrients or supplements leads to "better detoxification"? And do we need to avoid non-organic food, toothpaste and non-stick frying plans in avoid to avoid these toxins? This Quack Asylum episode evaluates these claims.

Study notes available at sigmanutrition.com/detox/

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With elevated LDL-cholesterol being a causal risk factor for atherosclerotic heart disease, having interventions to lower blood lipids, and in particular LDL-C, are crucial for population health. A number of drugs are now incredibly effective for this, with statins being the most widely used.

However, for those who do not wish to take a medication and/or have only a mild elevation, there may be potential for dietary intervention to lower LDL-C to a point where a statin (or other drug) is not needed.

A number of aspects of healthy dietary patterns have been known to reduce the liklihood of elevated blood lipids. Most notably perhaps, the ratio of polyunsaturated to saturated fat in the diet (P:S ratio). And an absolute low level of saturated fat in the diet (e.g. < 10% of calories).

However, work by Dr. David Jenkins and collegegues put forward the idea of a “portfolio” of specific nutrients/foods that could additionally lower LDL-C. This became known as the Portfolio Diet. The four primary pillars of this portfolio diet are: soy protein, viscous fibers, nuts, and plant sterols.

In this episode, Danny talks to the originator of this work, Dr. Jenkins.

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Some cognitive decline is normal with age. However, more significant cognitive decline is primarily due to disease-induced dementias (such as Alzheimer’s Disease). It also results from neurodegenerative disorders and chronic, prolonged degeneration of our neuronal pathways and functions. Drug discovery for dementias have been largely unsuccessful, leaving no good treatments for this collection of diseases. This had led to research examining areas that may aid in preventing (or more accurately, slowing) cognitive decline. In this episode the Sigma team look at the published data on a variety of nutrients, foods and dietary patterns, including: vitamin D, omega-3 fatty acids, B vitamins, caffeine, flavanoids, coffee and green leafy vegetables.

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• [00:02:01] Definitions
• [00:08:40] What causes cognitive decline? Dementia? Mechanisms of ND pathogenesis.
• [00:11:33] Why might nutrition play a role?
• [00:18:18] Dietary patterns
• [00:26:30] Diet interaction with APOE genotype
• [00:31:18] Alcohol
• [00:36:36] Polyphenols - mechanisms
• [00:43:05] Coffee & Caffeine
• [00:45:03] Flavanoids
• [00:51:04] Vitamin D
• [01:04:22] Omega 3 fatty acids
• [01:21:42] B vitamins & green leafy veg
• [01:30:35] Vitamin E
• [01:38:24] How to assess cognitive health in ageing intervention studies
• [01:45:28] Concluding thoughts

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• 02:02 – Framing of the GMOs debate
• 13:52 – Key definitions
• 20:34 – Where do GMOs show up in the food supply? And jurisdiction differences
• 33:40 – Impacts on human health and nutritional differences
• 45:16 – Impact on biodiversity
• 1:01:57 – What’s the deal with glyphosate herbicide?
• 1:05:34 – Concluding thoughts

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Coeliac disease is an autoimmune disorder stimulated by the ingestion of gluten, a protein found naturally in wheat, barley and rye. The condition affects approximately 1% of the Western world. However, currently the only approved treatment for coeliac disease is adherence to a gluten-free diet for life.

Therefore there is much research underway to develop alternative treatment options that may help these patients. One novel antigen-focused therapy that has been hypothesised is the use of plant bioactives.

Specifially, in vitro work by Dr. Charlene Van Buiten has looked as whether there is a mechanism by which polyphenols from green tea could be of benefit. Her work shows that these polyphenols can mitigate gliadin-mediated inflammation and intestinal permeability in vitro.

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Current discussions relating to health focus on longevity. This may include some who look at lifespan extension, some who talk of delaying or “treating” ageing or those who focus on reducing morbidity within the parameters of normal lifespan.

One propsed intervention that has garnered a lot of excitement, owing to some interesting research, is the potential use of fasting to increase longevity and/or healthspan. Within this broad category, various different dietary interventions have been suggested, including various forms of intermittent fasting, time-restricted eating, dietary restriction of certain nutritients, calorie restriction or a “fasting-mimicking” diet.

But what does the current evidence tell us? Does the evidence actually match the hype? In this episode Dr. Niamh Aspell, Alan Flanagan and Danny Lennon discuss some of the data on fasting and longevity.

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While dietary guidelines universally include fish as a food group that can be consumed regularly in a healthy dietary pattern, there are some potential risks of fish consumption that get raised. Some have some legitimacy, for example the frequency of consumption of high-mercury fish. However, other claims can go to extremes ("eating fish is bad for you") that are based in ideology rather than evidence.

In this Quack Asylum episode, we use a video made by a medical doctor as an example of where quackery can raise its head on this topic. Specifically, there are four claims made in the video that we investigate and see if there is any basis to them.

This is a Premium-exclusive episode. In order to listen to the full episode and access the show notes, you will need to subscribe to Sigma Nutrition Premium.

Many different diets have been put forward as solutions that treat type 2 diabetes. Some will claim the diet “reverses” diabetes, some say it puts it into “remission”, while others more conservatively recommend a diet to manage diabetes symptoms in a healthy way.

There has been some debate on the use of terms like reversal, cure or resolution. And recently more clarity has been found in defining each.

One of the diets that has been recommended by some for the purposes of “reversing” or treating diabetes is a low-fat, whole food plant-based (WFPB) diet. Specifically, there is a claim that it is superior to other diets in treating diabetes. Some of these claims relate to popular online diet & lifestyle programs that use such a diet. While there is also a number of studies that are commonly cited in support of the claims.

In this episode, we evaluate these claims by looking at the published research in this area, across epidemiology, human intervention trials and mechanistic rationale. We also ponder what it means for something to be the “best” diet to treat a chronic disease.

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• 03:15 - Sleep architecture and dimensions of sleep
• 10:29 - Influence of sleep on diet
• 35:11 - Chronotypes
• 53:26 - Impact of diet/meals on sleep
• 59:50 - Supplements like melatonin and tryptophan
• 1:20:27 - Rescuing a poor night's sleep - caffeine and nootropics
• 1:40:31 - Key Ideas segment (Premium only)

Omega-3 fatty acids have long been associated with various health outcomes. A type of omega-3 called alpha-linolenic acid (ALA) is found in various plant foods such as flax seeds or chia seeds. Other omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are found typically in marine food sources such as oily fish (e.g. salmon, mackerel) and algae. And while higher intakes of such foods have shown benefit, there has been some confusion over the benefit of such nutrients due to some large omega-3 supplementation trials reporting null findings. So what should we make of the current evidence base? Does supplementation lead to heart disease risk reduction or not? Do we need direct sources of EPA and DHA in the diet? Does ALA have unique benefits? What is an omega-3 index and why is it important? In this episode, fatty acid expert Dr. Bill Harris dives into each of these questions and clarifies what the current evidence tells us about the effect of these fatty acids on our health. Overview:

• 04:02 - Fatty acid definitions/subtypes
• 09:14 - Omega-3 status & the Omega-3 Index (O3I)
• 20:03 - Omega-3 supplementation trials for CVD
• 41:15 - DHA, brain health, cognition in later life, development, etc
• 49:45 - Should we be concerned about omega-6 fatty acids?

Show note available at: sigmanutrition.com/episode432/

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There is now widespread use of various "artificial sweeteners" in foods and beverages. Most commonly non-nutritive sweeteners are used to sweeten a products, whilst having less sugar and calories than a traditionally sugar-sweetened version of that product. For example, diet drinks (e.g. diet soda) are most commonly associated with artificial sweeteners. However, they are also in a wide variety of food products and supplements. For a long-time there has been skepticism and alarm raised about their potential health effects. From claims of them increasing our food intake, all the way to causing cancer. And food safety authorities have conducted rigorous examinations of the safety data on each of these compounds. In this episode, the Sigma team discuss the initial research that raised alarm bells, the current process of safety evaluation for non-nutritive sweeteners, the amounts they are consumed in, and the studies published thus far examining their health impacts. Access show notes here.

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1. Vegetables aren’t beneficial for health (or that there is no health benefit to high vegetable intake).
2. Vegetables are actually detrimental to health, and their removal improves health.

1. Humans are naturally carnivores, or have evolved to thrive on animal foods, and only turn to plants in times of famine.
2. Certain indigenous populations such as the Inuit or the Masai, eat close to no vegetables, yet have robust health.
3. Many of the nutrients present in vegetables can be obtained from animal foods. And beyond that, these nutrients are more bioavabilable when coming from animal sources.
4. Fibre is not an essential nutrient, and high-fibre diets don’t lead to the health benefits that are typically claimed.
5. Certain compounds in plants are actively harmful to us. Some of these compounds are natural pesticides, aimed to hurt us. Others are anti-nutrients, which decrease absorption of other key nutrients.
6. Plants/vegetables contain compounds/nutrients exacerbate clinical conditions such as IBS or autoimmune disorders, and removing all plants including veg, leads to improved outcomes in these people.
7. There is no benefit to a diet high in vegetables compared to a diet with low/no vegetable consumption.

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The popularity of soy foods and soy-based products has been increasing in recent times. This has been particularly the case as a dairy alternative, with people switching to using soy ‘milk’ and soy-based yogurts and cheese. Additionally, soy has become popular as a meat alternative in a variety of dishes for those looking to reduce meat intake. Soy foods such as tofu can be used in recipes in place of meat, and soy-based ‘meat alternatives’ that are vegetarian and vegan friendly have been developed.

With this increased prevalence, there has been some debate about the health effects of consuming soy foods and products. On one side, there have potential benefits highlighted of inclusion of soy in the diet. It contains phytoestrogens, which may have beneficial effects. Additionally, it is low in saturated fat, and so is potentially beneficial when used in place of saturated fat-rich foods.

However, some have claimed that the phytoestrogens (isoflavones specifically) in soy can be a cause for concern due to the ability of these compounds to mimic the effects of the hormone oestrogen. One common claim is that high soy intake is detrimental for men particularly, as it is “feminizing”; causing gynecomastia, loss of libido and erectile dysfunction.

So what is the truth? Is soy a health food? A harmful endocrine disruptor? Or simply neutral? In this episode we dive into the research and look at the evidence to date tells us about these questions. We consider two big health outcomes in particular; cardiovascular disease and breast cancer. And then final discuss what this means practically for our dietary choices.

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Click here to subscribe to Premium The pathogenesis of obesity is clearly complex. And the need to have a comprehensive model to explain this pathogenesis is important. One such model, termed the Energy Balance Model, has largely been the consensus paradigm of obesity scientists to this point. Specifically, a recently published paper in the American Journal of Clinical Nutrition by Dr. Kevin Hall and his colleagues outlined the various nuances of the model, as well as common misconceptions about the model. However, there are others who propose that this is not the correct model of obesity, but rather that obesity pathogenesis can be better explained by a model called the Carbohydrate-Insulin Model (CIM) of obesity. While this model has been proposed in various forms over the past couple of decades, the most recently published revision/update of this model was that put forward by Dr. David Ludwig and colleagues, in a Perspective published also in the AJCN, in December of 2021. In this episode, Dr. Kevin Hall (lead author of the paper mentioned above) and Dr. Stephan Guyenet are on the podcast to discuss the debate surrounding these two models. Specifically, the discussion will focus in on the Hall et al. (2022) and Ludwig et al. (2021) papers, as well as previous work leading up to both. Click here to access show notes for this episode

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Clearly the food choices one makes over time directly impacts health. However, choices are not made in a vacuum; that is, they are not always concious decisions made for rational reasons based on free will. Rather, the choices we make about food are shaped by the contexts within which they are made. The term "food environment" is used to describe the physical, economic, political and socio-cultural contexts in which choices are made about acquiring, preparing and consuming food.

As it was put in a paper published as part of The Lancet series on Obesity (2015), modern food environments "exploit people's biological, psychological, social, and economic vulnerability, making it easier for them to eat unhealthy foods".

In this episode the Sigma team discuss the implications of this, including a discussion of exactly which environmental conditions impact food choices and the evidence that exists for public health policy that may address the problematic aspects of modern food environments.

Topics:

• Intro to food environment [01:47]
• Food preferences [11:50]
• Disposable income/eat well guidelines [39:55]
• What can we do for a healthier population overall? Top down/bottom up [46:14
• Different types of public policy interventions [58:42]
• Stealth interventions [01:07:24]

You can access the show notes to this episode here.

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It's never been more popular to be seen as "evidence-based" as a fitness professional. And indeed evidence-based practice has been seen as the best way to arrive at coaching decisions. But is "evidence-based practice" actually what fitness professionals are doing? Is it even attainable for most coaches? Does it create a burden on them? Does it even matter if you're actually reading reserach or not? What makes for a competent personal trainer?

In this episode, Jacob Schepis is on the show to discuss all these questions and to discuss how he feels evidence-based practice fits within a framework of coaching and coach development.

Show notes can be found at sigmanutrition.com/episode427/

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Jaebien Rosario is currently a graduate level student in public health at East Stroudsburg University. He has degrees in psychology and philosophy, and has previously worked as a personal trainer and nutrition coach. His interest include science denialism, vaccine hesitancy, the philosophy of science, the sociology of science, and meta science.

His current research projects include research proposals for covid-19 and vitamin D trials, research conducted pertaining to local food banks and participation in coalitions for addressing food insecurity in northeast Pennsylvania.

Show notes at sigmanutrition.com/episode426/

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Prof. Anna Krylov is a Professor of Chemistry at the University of Southern California (USC), working in the field of theoretical and computational quantum chemistry. She has a M.Sc. in Chemistry from Moscow State University (1990) and a PhD from The Hebrew University of Jerusalem, Israel (1996).

Krylov is active in the promotion of gender equality in STEM fields, especially in theoretical chemistry. She created the web directory 'Women in Theoretical and Computational Chemistry, Material Science, and Biochemistry'. She has delivered several talks on gender equality in STEM.

In June 2021 she published a paper, "The Peril of Politicizing Science," has received over 75,000 views (as of February 2022) and is the all-time highest-ranked article in the Journal of Physical Chemistry Letters (impact factor of 6.5).

Show notes: sigmanutrition.com/episode425/

In this episode Alan and Danny discuss the role of cholesterol in the body and claims that are made suggesting low levels of blood cholesterol are harmful to health.

Starting with the premise that cholesterol is an important molecule in the body and plays a role in many processes, discussed are two related claims:

1. we should avoid low cholesterol levels as it can harm our health
2. elevated levels of cholesterol may actually be protective against disease or mortality.

The episode also critiques claims about cholesterol being “conditionally essential” and that low LDL-C/ApoB increases risk of mortality, cancer and infection.

Show notes at sigmanutrition.com/episode424/

Zoya Huschtscha, PhD is a researcher and assistant lecturer at Monash University (Australia), in the Department of Nutrition and Dietetics. She completed her PhD at the same institution, where her research focused on interventions to prevent and treat sarcopenia; i.e. the loss of muscle function and mass, typically with age. Zoya also has a Masters of Dietetics. In addition to her academic work, she works in private practice as a sports dietitian.

Show notes available at sigmanutrition.com/episode423/

In this episode the Sigma team discuss the research looking at psychobiotics, i.e. probiotics that have health impacts on those with pyschiatric disorders or symptoms. They discuss the origins of the research, the gut-brain axis, mechanisms by which gut microbiota could impact mood, and then the human trials to date that have examined probiotics' effects on mood, anxiety, depression, bipolar disorder and other outcomes.

Show notes can be found at sigmanutrition.com/episode422/ and the Sigma Statement on the gut-brain axis can be found at sigmanutrition.com/gut-brain-axis/

Dr. Brendon Stubbs, PhD, is a Senior Clinical Lecturer and researcher at King's College London, conducting research in physical activity & mental health, the mind-body interface, and meta-research. He has published over 600 academic papers in several leading journals across multiple scientific fields. He has informed policy guidelines in the UK, Europe and the World Health Organization.

Dr. Stubbs is also a clinical physiotherapist, being Head of Physiotherapy at the South London and Maudsley NHS Foundation Trust. He has a MSc in Neurological Rehabilitation & PhD in Pain Medicine & Rehabilitation.

Show notes to this episode are available at sigmanutrition.com/episode421/

Kevin Boehnke is a researcher at the University of Michigan, in the Chronic Pain and Fatigue Research Center. His current research focuses on therapeutic applications of illicit or semi-licit substances (cannabis, psychedelics). His goal is to rigorously assess appropriate use of these substances and to help address the public health harms caused by their criminalization.

Carrie Cuttler is an Assistant Professor at Washington State University. Her research at the Health and Cognition Laboratory there focuses on elucidating the potentially beneficial and detrimental effects of chronic cannabis use and acute cannabis intoxication. Her recent work has focused on examining links between cannabis use and mental health (e.g., ADHD, PTSD, OCD, depression, anxiety).

Show notes available at sigmanutrition.com/episode420/

Dr. Nathan Bryan, PhD is an Adjunct Assistant Professor at Baylor College of Medicine. Dr. Bryan has been involved in nitric oxide research for the past 18 years and has made many seminal discoveries in the field. He was the first to demonstrate and discover an endocrine function of nitric oxide via the formation of S-nitrosoglutathione and inorganic nitrite.

Dr. Bryan obtained his doctoral degree from Louisiana State University School of Medicine in Shreveport where he was the recipient of the Dean’s Award for Excellence in Research. He pursued his post-doctoral training as a Kirschstein Fellow at Boston University School of Medicine in the Whitaker Cardiovascular Institute. After a two year post-doctoral fellowship, in 2006 Dr. Bryan was recruited to join faculty at the University of Texas Health Science Center at Houston by Ferid Murad, M.D., Ph.D., 1998 Nobel Laureate in Medicine or Physiology.

Show notes at sigmanutrition.com/episode419/

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In this episode Danny and Alan discuss the debate around whether a direct source of the long-chain omega-3 fatty acid DHA should be recommended. Many people do not consume the marine foods (primarily fatty fish) that contain DHA, and higher DHA intakes, DHA status, and omega-3 indices are predictive of certain health outcomes.

But the essential omega-3 fatty acid alpha-linolenic acid (ALA) can be consumed from plant sources. So do those who do not consume direct sources of DHA have lower DHA status? Does this matter? And if so, then what pragmatic conclusions can we come to? All of this is covered in this episode.

Show notes available at sigmanutrition.com/episode418/

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Dr. Austin Baraki joins Danny and Alan to critically evaluate the assumption that blood levels of a nutrient directly tell us about overall nutritional status. With many people getting blood tests done outside of clinical settings, there is significant risk of misinterpretation of what these measures mean. In this episode we discuss measures of calcium, sodium, vitamin D and others as examples of where misinterpretation and misunderstanding can happen.

Show notes can be found at sigmanutrition.com/episode417/

Dr. David Nunan, PhD is a Lecturer and Senior Research Fellow in the Centre for Evidence-Based Medicine at the University of Oxford. There, he is the Director of the Postgraduate Certificate in 'Teaching Evidence-Based Health Care' and the lead tutor for the internationally-renowned 'Teaching Evidence-Based Medicine' course.

He is a principal investigator with research interests in prevention and treatment of lifestyle-related conditions, improving the understanding and use of research evidence, and meta-epidemiology (research on research). David has experience in a breadth of methodologies including diagnostic studies, statistical analysis, qualitative research and clinical trials.

Show notes available at sigmanutrition.com/episode416

Bruce Neal is Executive Director at The George Institute for Global Health Australia; and Professor of Medicine, UNSW Sydney.

Prof Neal is a UK-trained physician who has 25 years’ experience in clinical, epidemiological, and public health research with a focus on heart disease, stroke and diabetes. Bruce has a longstanding interest in high blood pressure and diabetes and the potential for both clinical interventions and changes in the food supply to deliver health gains. His work has been characterised by its focus on collaboration, quantitation, translation and impact.

He holds professorial appointments at UNSW Sydney, Imperial College London, and an honorary appointment at the University of Sydney. He has published some 450 scientific papers and since 2016 has been identified by Thomson Reuters as one of ‘The World’s Most Influential Scientific Minds’, an acknowledgement provided to just a few thousand researchers across all disciplines, worldwide.

He has particular expertise in the conduct of large-scale clinical trials addressing cardiovascular disease but has also done a significant body of work addressing food policy issues related to sugars, fats, portion size and food labelling.

Find the show notes at sigmanutrition.com/episode415/

In this episode, the Sigma team discuss the claim that machine learning and data science may overtake traditional research methods in nutrition.  They discuss how machine learning could solve some current limitations of traditional methods, studies on its use so far, potential applications in future trials, and potential limitations or problems with the increased use of data science (including ethical and societal concerns). They also ponder on how tech is currently being used (and abused) in relation to personalised nutrition, tech products, continuous glucose monitoring use, among other things.

Anthony Fardet, PhD is a nutrition science researcher in the Human Nutrition Unit at Université Clermont Auvergne, France. His work has focused on a number of related areas; the consequences of the reductionist and holistic approaches applied to nutrition research, the relevance of a new classification of foods based on their degree of processing, and the role of the complex structure of the food in its health potential ("matrix effect"). You can find the show notes to this episode at sigmanutrition.com/episode413/

Dr. Eirini Dimidi of King’s College London discusses the research on diet in chronic constipation and functional bowel disorders. Dr. Dimidi is a Lecturer in Nutritional Sciences and a Registered Dietitian. In 2016, she was appointed as a Research Associate at King’s College London, where she undertook several research projects on the impact of nutritional interventions in gut function and dysfunction.

Dr. Dimidi is undertaking research on nutrition-based interventions, including fibre, plant foods, prebiotics, probiotics, and the low FODMAP diet, in gastrointestinal health. Her primary focus is to advance the understanding of the impact of dietary therapies in functional bowel disorders, including chronic constipation and irritable bowel syndrome.

You can find the show notes to this episode at sigmanutrition.com/episode412/

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In this episode Alan and Danny discuss the role of nutrition in bone health. They cover the importance of bone health, bone disorders such as osteoporosis, how nutrients play a role in bone remodelling, and the evidence of dietary and supplementation trials on bone health outcomes.

You can find the show notes, with links to all the reference studies, at https://sigmanutrition.com/episode411/ 

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In this episode Alan and Danny answer a variety of questions sent in from listeners.

Questions:

[1:10] Gabriel - Is there any benefit to including SFAs and cholesterol in low quantities in our diets for healthspan?

[10:42] Luis Arrondo - Can I do 3 rather than 4 meals or more for protein absorption by increasing grams of protein? How many grams of protein can be absorbed at one sitting. Does taking in protein at night help more absorption of protein? If so, something slower, like milk over whey? Last, how much protein per kilo of weight to gain muscle via weightlifing?

[19:34] Heather Smith - Please could you go into the sodium needs of those with hypotension. Your podcast about normotension and hypertension was excellent, as was the section relating to athletes. I’d love to hear your thoughts on the sodium needs of a hypotensive person. Thank you!

[27:00] Judith Williams - I would find it really helpful if you could summarise what the evidence shows are the key dietary changes for long term weight loss. [36:41] Dale Grant - Great podcast and episode as normal especially the quack asylum (big fan of this segment). Having listened to a few of these extreme people (quacks) on various platforms, I’ve noticed they also employ an aggressive falsify my opponents position tactic. Its almost as if they are aware of Karl Poppers falsification principle, but have misinterpreted it as falsify my "opponents" position instead of my own. Aside from the fact they falsely view the person they are having a debate with as their “opponent”, they miss the point that they should be trying to find evidence to falsify their own position, and thus get closer to a capital T Truth. On the other hand as Alan pointed out with Assem Mahlhotra, this may just be a reluctance to acknowledge evidence for other reasons (narcissism, us vs Them narrative, etc). Nowhere was this more apparent than when James Wilks (host of mass propaganda film game changers), sought to aggressively debate Chris Kresser on the Joe Rogan Podcast. Considering Wilks is a former cage fighter this wasn’t surprising. Unfortunately, this aggressive tactic does lead some people to conclude that Wilks has “won” the argument, because he has “won” the debate. Similar to most modern debates, it seems like you don’t have to win the debate intellectually with reason. Instead you just have to make it seem as if your more competent than your opponent. Do you agree these extreme people employ this tactic? and how do you think we could improve “scientific” debates (note inverted commas) in the public domain in the future? [46:40] Dimitri - Should fruit consumption be moderated because of the sugar content? For example, a fig has 8g of sugar, can I eat 5-10 in one sitting or would that be detrimental to health?

[51:26] Rebecca Toutant - What is the evidence / practice behind integrative and functional nutrition?

[56:06] Duncan Clarke - This will be a strange question for you but I'll send it anyway. How could a cyclist specifically lose upper body muscle mass? For example a fit healthy athlete from another sport takes up cycling and they now have more arm/shoulder muscle than needed. The goal being to maximize the power to weight ratio for climbing.

[60:15] Gabriel - Do you foresee any public health issues related to the increasing popularity of plant based diets, where less careful individuals may face issues consuming certain nutrients harder to get from a plant based diet, such as preformed Vitamin A, choline, iron, protein etc?

[72:03] Ward Stanford - After re-listening to your podcast on weight maintenance over time I was wondering what information exists on the idea of establishing new body fat set points. It seems like merely existing at a lower bf% for a period of time may not be enough, but what are your thoughts on one's ability to truly create a lower set point where it becomes easier to maintain a lower body fat, and how long would you need to be at that lower bf% for it to become a "set point" Thank you!

In this episode nutritionist Simon Hill discusses the barriers to eating a healthy diet, steps that can be taken to shift both individuals and the general population to a healthier dietary patten, and a number of other topics. Find the show notes at sigmanutrition.com/episode409/ 

Dr. Mario Kratz is a clinical researcher in the areas of nutrition, obesity, and cardiometabolic disease, with more than 20 years of experience running clinical studies in a variety of populations. He is a former research associate professor at the University of Washington in the departments of Medicine and Epidemiology. And is also formerly an Associate Professor at the Fred Hutchinson Cancer Research Center in Washington state.

You can find the show notes at sigmanutrition.com/episode408/ or you can support the show on patreon.com/sigmanutrition/

In this episode we discuss the potential impact of dietary polyphenols on cardiovascular disease risk; including impacts on blood pressure, flow-mediated dilation, and other related outcomes. We talk about some potential mechanisms and then several specific randomized, controlled trials.

You can find the show notes at sigmanutrition.com/episode407/ and you can support the podcast on patreon.com/sigmanutrition

In this episode we discuss the potential impact of dietary polyphenols on cognitive health; including cogitnitve funciton, memory, and risk of dementia and Alzeimher's. We talk about some potential mechanisms, cohort studies, and then direct controlled trials.

You can find the show notes at sigmanutrition.com/episode406/ and/or support the podcast at patreon.com/sigmanutrition

Dr Adrian Brown is a NIHR Lecturer and Research Fellow in the Centre of Obesity Research at University College London. He is also a senior Specialist Weight Management and Bariatric dietitian with over 15 years of clinical experience and a PhD in Medicine from Imperial College London.

His research interests centre around obesity, type 2 diabetes, bariatric surgery, weight stigma and the use of formula-based diets in different patient populations. He is an Honorary Academic for Public Health England Obesity and Healthy Weight Team, on the strategic council for APPG on Obesity and is on the scientific council of the British Nutrition Foundation.

You can find the show notes to this episode at sigmanutrition.com/episode404/ and you can support the podcast at patreon.com/sigmanutrition/

Prof. Marion Hetherington is Professor of Biopsychology at University of Leeds, where her research is focused on the psychology of appetite across the lifespan. She has previously been at Johns Hopkins, the NIH, the University of Dundee, University of Liverpool and Glasgow Caledonian University, before taking up her role in Leeds in 2008, where she works within the Human Appetite Research Unit. You can find the show notes to this episode at sigmanutrition.com/episode404/ and you can support the podcast at patreon.com/sigmanutrition

Prof. David Jacobs, PhD is Professor of Public Health, in the Division of Epidemiology and Community Health, at the University of Minnesota. He has published highly inflential work in nutritional epidemiology and health epidemiolgy for decades. A number of his papers have brought up crucially important ideas about how to do good nutrition science. Specifically, he has talked about think of whole diet or foods as the exposure of interest, rather than individual nutrients. Essentially warning against the pitfalls of applying a biomedical lens to nutrition research. You can find the show notes to this episode at sigmanutrition.com/episode403/

Prof. Leanne Redman is a Professor of Reproductive Endocrinology & Women’s Health, based at the Pennington Biomedical Research Center. As the director of the Reproductive Endocrinology and Women’s Health Laboratory, she is focused on understanding the intergenerational transmission of obesity. She has published on maternal diet, preeclampsia, and gestational diabetes, amoung other issues. She and her colleagues are currently conducting a rigorous trial to determine the effects of a 6-month gestational intervention with calorie restriction and food provision to promote maternal weight maintenance and fat loss in 100 pregnant women with grades 2 and 3 obesity.

Show notes are available at sigmanutrition.com/episode402/

You can support the podcast at patreon.com/sigmanutrition/

We take a look at three more "quacks" who spread misinformation; Dr. Michael Greger (01:21), Eric Berg (36:26), and Dr. Paul Saladino (55:18). We give reference to some specific examples.

Show notes available at sigmanutrition.com/episode401/

If you wish to support the podcast you can do so via patreon.com/sigmanutrition/

Links: 

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About This Episode:

To celebrate our 400th episode, we take a look at two "quacks" who spread misinformation; Dr. Aseem Malhotra and Dr. James DiNicolantonio. We give reference to some specific examples.

James Betts is Professor of Metabolic Physiology at the University of Bath, where he is Co-Director of the Centre for Nutrition, Exercise & Metabolism. His research employs randomised controlled trials to study the effects of nutrition on metabolic regulation.

His group recently published a trial aiming to separate out the effects of fasting from those of calorie restriction.

Show notes at sigmanutrition.com/episode399/

Carole Hooven, PhD, is lecturer and codirector of undergraduate studies in the Department of Human Evolutionary Biology at Harvard University. She earned her PhD at Harvard, studying behavioral endocrinology and evolution of sex differences in humans (physiology, behavior and cognition). She has recently written a book on how testosterone influences behaviour and explains many sex differences. The book is titled 'T: The Story of Testosterone, the Hormone that Dominates and Divides Us'.

Show notes available at sigmanutrition.com/episode398/

In this episode Danny & Alan discuss the impacts of nitrates and nitrites on health. They look at the beneficial impacts of dietary nitrate, as well as issues around nitrites in processed meat.

Show notes available at sigmanutrition.com/episode397/

Dr. Leigh Frame, PhD is Director of Integrative Medicine at George Washington School of Medicine and Health Sciences in Washington DC. Dr. Frame received her PhD in Human Nutrition, as well as a Master of Health Science degree in Molecular Microbiology and Immunology, from the Johns Hopkins Bloomberg School of Public Health.

In this episode we discuss a range of topics including: the role of placebo groups and the different types we see in nutrient supplementation trials, potential ethical issues, and the development of research ethics.

Show notes available at sigmanutrition.com/epsiode396/

Professor le Roux is an expert in metabolic medicine and is currently a Professor of Experimental Pathology, University College Dublin. He is recognised as a world leader in metabolism and obesity.

Professor le Roux’s clinical focus is in the management of Type 2 diabetes, pre-diabetes, obesity, cardiovascular risk and other metabolic disorders. Professor Carel le Roux has been published extensively and currently holds a number of editorial roles for journals in his field including, Clinical Obesity and Surgery for Obesity and Related Diseases.

Show notes are available at: sigmanutrition.com/episode395

Gar Benn is the Head of Coaching at Sigma Nutrition, where he works with nutrition coaching clients and oversees the coaching services.

He is the owner of CityGym Limerick, a powerlifting-centric gym in Ireland. And he is also the co-founder of the European Powerlifting Confernce and Titan Ireland.

Gar is a qualifed nutrition coach and has completed courses in Motivational Interviewing and Acceptance and Commitment Therapy (ACT).

Show notes at sigmanutrition.com/episode394/

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Vitamin D status is linked to a variety of health outcomes, and avoiding or correcting deficiency is important. However, does supplementing with vitamin D actually benefit most people? Is there evidence for supplementation improving health outcomes like mortality, cancer risk, depression or other outcomes? In this episode Danny and Alan look at intervention trials of vitamin D supplementation.

Show notes available at: https://sigmanutrition.com/episode393/

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Dr. Clare Pettinger is a Registered Dietitian, Public Health Nutritionist and experienced educator. Dr. Pettinger publishes research in the public health nutrition field, and lectures at the Universtity of Plymouth, UK. 

Dr. Pettinger is actively engaged in community-focussed research around food systems, poverty and social justice. She is an enthusiastic 'sustainability advocate' involved in promoting environmentally sustainable diets for nutrition professionals and Allied Health Professioinals. 

Show notes available at sigmanutrition.com/episode392

In this episode Danny and Alan discuss the three primary models used to explain body mass regulation: 1) Set Point Model, 2) Settling Point Model, 3) Dual Intervention Model. They discuss the role of feedback systems, environment, behaviour, as well as discussing both the "thrifty gene hypothesis" and John Speakman's "drifty gene hypothesis".

• Dairy: is it over-emphasized in the Dietary Guidelines for Americans?
• Dairy tolerance
• Critical importance of substitution effects
• Differences between difference types of dairy on health
• Claims by some WFPB advocates that olive oil can negatively impact endothethial function
• Distinguishing between acute and chronic effects
• Gil's work with Antonio Damasio on feelings

Renee McGregor is a leading sports dietitian, specialising in Eating Disorders, REDs, The Female Athlete, athlete health and performance.

She is regularly asked to work directly with high performing and professional athletes that have developed a dysfunctional relationship with food that is impacting their performance, health and career. Her practice and knowledge is supported by extensive experience of working in both clinical and performance nutrition, including, Olympic, Paralympic and Commonwealth teams.

She is the co-founder and director of #TRAINBRAVE a campaign raising the awareness of eating disorders in sport; providing resources and practical strategies to reduce the prevalence.

She is on the REDS advisory board for BASES (The British Association of Sport and Exercise Science) and sits on the International Task Force for Orthorexia.

Find the show notes at sigmanutrition.com/episode389

Danny & Alan discuss the current evidence on the health consequences and societal consequences of weight stigma and weigh bias. This includes implicit bias, explicit bias, and internalization of bias. What evidence do we currently have? And what questions remain unanswered?

Segments:

You can find the show notes to this episode at sigmanutrition.com/episode388

If you wish to support the podcast you can do so on Patreon at patreon.com/sigmanutrition or directly via the site at sigmanutrition.com/donate

In this episode Danny and Alan discuss the relationship between shift work and health. Why does shift work have negative health impacts? How can one mitigate circadian misalignment? How does shift work impact nutrient metabolism? What nutrition, sleep and lifestyle strategies can help shift workers? 

Show notes at: sigmanutrition.com/episode387

Dr. Tobias is a nutrition and obesity epidemiologist at the Brigham and Women’s Hospital and Harvard Medical School in Boston, MA. She received doctoral and postdoctoral training from the Harvard TH Chan School of Public Health, Boston, MA, under mentor Dr. Frank B. Hu.

Dr. Tobias is co-Instructor of Nutrition Epidemiology with Dr. Walter Willett and faculty member at the Harvard TH Chan School of Public Health. Her epidemiologic research focuses on identifying lifestyle risk factors and underlying mechanisms related to obesity and its major chronic diseases, including type 2 diabetes and cancer.

Dr. Tobias is currently the Academic Editor for the American Journal of Clinical Nutrition.

Show notes at sigmanutrition.com/episode386

In this episode we explore the causes of insulin resistance, and the dietary modifications that may help those with insulin resistance.

We discuss how insulin resistance is a complex metabolic disorder, that goes beyond one single pathway or cause. There is also a discussion on the mechanisms of insulin resistance pathogenesis. Specifically, we talk about the accumulation of ectopic fat. Ectopic fat is the storage of triglycerides in tissues other than fat tissue, such as the liver, skeletal muscle, heart, and pancreas.

There is also an overview of the Twin-Cycle Hypothesis, which was discussed in more detail in a previous episode with Prof. Roy Taylor. In addition, we give special mention to liver fat accumulation and the relationship between insulin resistance and non-alcoholic fatty liver disease (NAFLD).

Then various diet interventions are assessed for their potential usefulness to those with insulin resistnace. This includes different diet types (e.g. whole-food plant-based diet, low-carbohydrate ketogenic diet, etc.), role of macronutrients, pre-loading studies, and the role of meal timing and circadian effects.

Find the show notes at https://sigmanutrition.com/episode385

In this episode Greg Nuckols and Mike Zourdos breakdown two research papers related to the interference effect and concurrent training. 

Greg and Mike (along with Eric Helms and Eric Trexler) produce the MASS research review, which breaks down the latest research studies relevant to those interested in strength training, strength sports, and bodybuilding. 

From April 27th to May 4th you can get a significant discount on a MASS subscription by visiting sigmanutrition.com/mass-sale/

In this episode Danny and Alan discuss irritable bowel syndome and the evidence related to dietary interventions. They discuss diagnosis of the condition, various sub-types, potential mechanisms, the gut-brain axis, first line treatments, impact of fibre, and evidence on the low FODMAP diet.

Today's Topic in Focus: IBS & Diet [06:20]

"I Have a Question!" [74:47]

Quack Asylum [79:30]

Random Recommendations [86:49]

Show notes available at sigmanutrition.com/episode383

Andy Morgan is the founder of RippedBody.com and an online coach. He co-authored the Muscle & Strength Pyramids books along with Dr. Eric Helms and Andrea Valdez. He has published a host of excellent nutrition and training resources in the form of ebooks, articles and podcasts, which can be found on the Ripped Body website. He recently released the third edition of the Diet Adjustments Manual.

You can find the show notes to this episode at: sigmanutrition.com/episode382

Prof. Chris Packard holds an Honorary Professorship of Vascular Biochemistry at the University of Glasgow. Over his career, Professor Packard has focussed on two aspects of atherosclerosis research, lipoprotein metabolism and how it is affected by diets and drugs, and large-scale clinical trials of lipid lowering agents. He is acknowledged as one of the leading researchers in the world in this field.

Show notes available at sigmanutrition.com/episode381

Prof. Barry Popkin is the W.R. Kenan Jr. Distinguished Professor of Nutrition at the University of North Carolina at Chapel Hill. He is a nutrition and obesity researcher at the Carolina Population Center and is the director of the Interdisciplinary Center for Obesity at UNC.

He developed the concept of the Nutrition Transition, the study of the dynamic shifts in dietary intake and physical activity patterns and trends around obesity and other nutrition-related noncommunicable diseases (NCD). Prof. Popkin is involved now in work on program and policy design at the national level to improve the average diet at the population level.

He has published more than 545 journal articles, and is one of the most cited nutrition scholars in the world, with more than 90,000 citations.

Show notes available at sigmanutrition.com/episode380

Danny and Alan are joined by Dr. Spencer Nadolsky. Dr. Nadolsky is a board-certified obesity specialist, lipidologist, and family physician.

In this episode we discuss the strengths and limitations of BMI, adipose tissue type and relevance to risk, hypertrophic vs. hyperplastic adipocytes, 'Metabolically Healthy Obesity', and weight stigma.

Show notes available at sigmanutrition.com/episode379