Sigma Nutrition Radio

Epizode

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  #620: BPC-157 and Peptide Medications: What Do We Know? – Jordan Feigenbaum, MD 15.09.2026 57min

  Commonly people are talking about "peptides" to refer to a heterogeneous group of peptide medications or investigational compounds. These are increasingly promoted for injury recovery, tissue repair, performance and longevity, with BPC-157 attracting particular attention. But what evidence supports the claims made about these compounds? How should animal studies, biological mechanisms and personal anecdotes be interpreted? What is currently known about their safety? And what do recent regulatory discussions actually mean for their medical status and availability? In this episode, physician and Barbell Medicine founder Dr. Jordan Feigenbaum examines the evidence surrounding BPC-157 and other peptide medications, alongside the wider questions of risk, access and informed decision-making. Timestamps [00:13] What we want to address [04:47] Interview start [05:29] What do we mean by "peptides"? [10:32] BPC-157 evidence [16:49] Sourcing of peptides [20:19] The gray zone of pro-peptide communication [24:16] Risk sourcing vs drug effects [26:25] FDA lists and compounding [31:05] Risk tolerance and informed consent [43:02] Why did pharma abandon peptide research? [47:44] Harm reduction debate [51:48] Practical takeaways [56:20] Key Ideas segment (Premium members only) Episode Resources Go to episode page  Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Barbell Medicine Instagram: jordan_barbellmedicine Book: Signal: What Testosterone Levels Are Telling You About Your Health Related episode: #524: Strength & Fitness Levels for Reducing Chronic Disease Risk & Promoting Health Ageing – Jordan Feigenbaum, MD Further reading: Emerging use of BPC-157 in orthopaedic sports medicine: a systematic review. 2025. Ruenzi M, Stolte M, Veljaca M, et al. Efficacy and safety of PL 14736 (BPC 157) in patients with active ulcerative colitis. Gastroenterology. 2005. Meeting abstract; full study not published.
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  #619: How Much Fish Should a Healthy Diet Contain? 08.09.2026 1h 3min

  Most dietary guidelines recommend eating one to two servings of fish per week, often specifying that at least one serving should be oily fish. But how directly is that recommendation supported by evidence? And does adding fish to the diet improve outcomes? This episode examines where current fish-intake recommendations originated, why findings may appear contradictory, and what substitution analyses can tell us about replacing fish with alternative options. It also considers evidence from pescatarian and vegetarian cohorts, including whether adding fish would improve an already high-quality diet and whether removing it from a plant-forward diet is likely to provide further benefit. Timestamps [00:20] Setting out the question at hand [03:26] Overview of typical fish intake recommendations [07:10] Is there good evidence for suggested intakes? [08:10] Historical context [13:22] Key evidence: DART trial and cohort data [19:27] Analysis from Mohan et al. [25:04] Comparator issue: what is fish replacing? [30:52] Fish protein vs. plant protein [44:29] Vegetarian vs. pescatarian cohorts [55:20] Conclusions [01:00:50] Key Ideas segment (Premium-only) Episode Resources Go to episode page (with full study reference list) Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Subscribe to Alan's Alinea Nutrition Education Hub Enroll in the next cohort of our Applied Nutrition Literacy course
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  #618: How Wellness & Optimisation Culture Can Commodify Science – Nick Tiller, PhD 01.09.2026 56min

  Wellness and optimisation culture increasingly presents itself as "science-based". But citing studies, using technical language, or having scientific credentials does not guarantee that the underlying evidence is being represented accurately. In this episode, exercise science researcher Dr. Nick Tiller, discusses how science can be selectively packaged, overstated, and used to support commercially attractive health claims. It explores the difference between science communication and science commodification, why scientific scepticism is distinct from cynicism, how anecdotes and mechanistic explanations can mislead, and why a single peer-reviewed study should never be treated as definitive evidence. The conversation also looks further upstream at problems within science itself, including low statistical power, p-hacking, publication bias, questionable research practices, and academic incentives that may favour novelty and positive findings. These issues can then be amplified through media, social platforms, and the wellness industry until tentative findings become confident recommendations. Timestamps: [03:14] Interview start [06:22] The health and wellness "lie" [08:38] Optimization and the illusion of control [11:14] Science communicators vs commodifiers [14:21] Vitamin D hype case study [20:54] Spotting misinformation online [24:50] Skepticism not cynicism [28:47] Guidelines for debunking [33:46] Spotting the grift pattern [41:25] Bad science in academia [54:47] Key ideas segment (Premium-only) Episode Resources: Go to episode page Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Dr. Tiller's website Tiller & Phillips, 2023 – How Skepticism (not Cynicism) Can Raise Scientific Standards and Reform the Health and Wellness Industry Tiller et al., 2024 – The Nontechnical Summary: A New Initiative to Enhance the Translation of Sports Science Research and Reduce the Spread of Misinformation
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  #617: What Does Effective Athlete Support Look Like in Practice? – Gemma McGuinness 25.08.2026 46min

  Effective athlete support requires more than delivering technically correct nutrition advice. It depends on understanding the athlete's wider environment, anticipating the pressures that disrupt good intentions, and building flexible routines that remain useful across training, competition, travel and everyday life. This episode explores how practitioners can move beyond rigid prescriptions, use "good, better, best" options, measure meaningful progress, and create environments in which athletes can communicate openly about difficulties. It also examines identity, transitions out of sport, and why sustainable support should develop an athlete's autonomy rather than dependence on the practitioner. To discuss all this is Gemma McGuinness, registered performance nutritionist, former professional footballer and co-founder of Verus Performance. Timestamps: [02:38] Interview start [03:48] Nutrition beyond performance [10:10] Identity and food choices [18:47] Standards versus perfectionism [24:52] Planning that actually works [28:32] Measuring progress in athletes [33:37] Where discipline can cause problems [38:40] Building high performance environments [45:37] Key ideas (Premium-only) Links: Go to episode page Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Instagram: @gemmcguinnness Verus Performance Davey Nutrition Gemma's Substack
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  Fiber: Independent Benefits or Just a Proxy for Healthy Foods? 18.08.2026 21min

  This episode answers one of the questions raised in the most recent Q&A episode on Sigma Nutrition Premium.  The full episode includes the following questions: Fiber: Independent effect or proxy for healthy foods? Exposure frequency for matched dose of red meat MTHFR gene mutations and 5-MTHF Typical fish oil supplements vs pharmaceutical-grade products Health impacts of saturated fat in coconut products Do I need to consume whole grains? Could the increasing use of AI pose a threat to doing rigorous science? To listen to the entire episode (plus the back catalogue of all Premium-exclusive episodes) become a member of Sigma Nutrition Premium. For episode info and mentioned research go to the episode page here.
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  #616: More Testing, Better Health? Harms of Overdiagnosis & Overtreatment - Austin Baraki, MD 11.08.2026 1h 15min

  Medical screening is often framed as an uncomplicated good: if disease is found earlier, treatment can begin earlier and outcomes should improve. This episode examines why that reasoning is incomplete. Screening can produce benefit, but it can also generate false positives, incidental findings, overdiagnosis, overtreatment and diagnostic cascades. Dr. Austin Baraki discusses the distinction between screening people without relevant symptoms and investigating a clinical problem, the probabilistic interpretation of test results, biases that can make screening appear more effective than it is, and the importance of shared decision-making before a test is ordered. Timestamps: [03:35] What screening means [06:36] Choosing what to screen [11:59] Sensitivity and specificity [16:54] Predictive value and prevalence [22:16] Harms of screening and testing [31:02] Overdiagnosis and biases [41:40] The $50,000 physical [44:49] Overdiagnosis vs false positives [53:03] Overtreatment and surveillance [57:22] Clinician action bias [01:02:30] What to screen for Links: Go to episode page (with resources) Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Instagram: @austin_barbellmedicine Twitter: @AustinBaraki
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  #615: Why Processing Doesn't Determine the Healthfulness of Plant-Based Diets – Alysha Thompson, PhD 04.08.2026 56min

  What does the evidence actually show when we look at plant-based dietary patterns through the lens of food processing? And does classifying foods as "ultra-processed" meaningfully change how we interpret the relationship between plant-based diets and long-term health outcomes? A recent large prospective cohort analysis examined both healthful and unhealthful plant-based dietary patterns, and importantly, stratified the contributing foods based on whether they were classified as ultra-processed or non-ultra-processed. In this episode, the study's lead author Dr Alysha Thompson, discusses the many intesresting aspects to the analysis. These include how the dietary indices were constructed, the challenges of applying NOVA classification to self-reported dietary data, the role of residual confounding in observational nutrition research, and the extent to which we can or cannot infer independent effects of processing from these findings. We also consider the broader implications for the use of processing-based classifications in nutrition science and whether this adds meaningful explanatory value beyond traditional assessments of diet quality. Timestamps [03:02] Interview start [05:08] The key research question [07:52] Study design [17:25] Building diet scores [21:11] NOVA classification challenges [25:04] Key findings [38:30] NOVA debate and stance [43:44] Adjustments and mediators [48:11] Future research directions [54:37] Key ideas (premium-only) Resources: Go to episode page Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Paper: Plant-Based Diets, Ultra-Processed Foods, and Risks of Mortality and Major Chronic Diseases: A Prospective Cohort Study
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  #614: The Human Skills of Nutrition Coaching – Krista Scott-Dixon, PhD 21.07.2026 56min

  In nutrition and health coaching, one of the central challenges is understanding how people actually change, particularly when life is complex, motivation fluctuates, and behaviour is shaped by emotion, identity, environment, and relationships. In this episode, Dr. Krista Scott-Dixon discusses the human skills that underpin effective coaching practice. We discuss the importance of the coach–client relationship, the role of therapeutic alliance, and how concepts from counselling and psychology can be used appropriately within scope of practice. The discussion also explores autonomy-supportive coaching, self-regulation, compassion, acceptance, feedback, and the meta-skills practitioners need in order to improve over time. Timestamps [06:10] What makes a competent practitioners? [11:17] Scope of practice line [17:49] Therapeutic alliance [23:33] Applying compassion and acceptance [31:18] LLMs vs human connection [34:40] Meta skills for practitioners [38:51] Getting better feedback [44:23] Collaboration and autonomy [55:44] Key ideas recap Links: Go to episode page Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Past episode #326: Adaptability & Autonomy in the Nutrition Coaching Process Krista's website: kristascottdixon.com Instagram: @stumptuous 1% Better Academy The textbook: Applied Nutrition Coaching and Counseling: ebook version US Canada UK International
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  #613: Supplement Safety & Medication Interactions – Giulia Guerrini, MPharm 14.07.2026 57min

  Supplement safety is often discussed in very general terms, but in practice the risks depend heavily on the individual. A supplement that is reasonable for one person may be inappropriate for another based on their medications, health conditions, dose, formulation, or the other products they are already using. This becomes especially important when supplements interact with medications or underlying medical conditions. Some interactions can change how a drug is absorbed, metabolised, transported, or cleared from the body. Others can amplify or oppose the drug's clinical effect, such as increasing sedation, lowering blood pressure or blood glucose, or affecting bleeding risk. In this episode, Giulia Guerrini, a GPhC-registered pharmacist and researcher at Examine, talks about how clinicians and practitioners can think more systematically about supplement safety, side effects, contraindications, and drug–supplement interactions. Timestamps: [02:39] Interview start [05:21] Why context matters [06:38] Timing and formulation [12:58] Rating interaction risk [22:39] Berberine benefits and interactions [27:33] Adaptogens quality concerns [30:15] Melatonin safety questions [36:30] Stacking supplements risks [41:50] Quality control and regulation [55:35] Key ideas segment (premium-only) Links: Free trial of Examine Clinician Edition – For health & nutrition professionals. Includes the Supplement Navigator (safety and interaction checking), plus all other Examine tools (study summaries, supplement database, in-depth guides, etc.) Free trial of Examine+ – For anyone wanting to make evidence-based decisions about supplements and health. Includes: 100+ study summaries a month. The full supplement database. In-depth guides. ExamineAI. Doesn't include the Supplement Navigator. Go to episode page Subscribe to Sigma Nutrition Premium
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  #612: Does Sweet Taste Exposure Actually Develop Preference? – Prof. Katherine Appleton 07.07.2026 38min

  A common idea is that repeated exposure to sweet taste strengthens our preference for sweetness, which then drives greater intake of sweet foods and drinks. This idea is often used in arguments about fruit, low-calorie sweeteners, diet drinks, and the supposed need to "reset" taste preferences by avoiding sweetness altogether. But does the evidence actually support that causal chain? In this episode, Prof. Katherine Appleton, Professor of Psychology at Bournemouth University, discusses what is known about sweet taste exposure, sweet preference, and how these concepts are measured in the scientific literature. Timestamps: [04:23] Interview starts [07:35] Sweetness terms explained [10:17] Sweet liker phenotypes [14:03] Liking vs wanting vs preference [19:18] Trial evidence overview [23:48] Policy and practical impact [30:41] Why we eat foods Links: Go to episode page (incl. links to studies) Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course
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  #611: Electrolyte Mythology: Wellness Marketing vs. Evidence - Zoë Rom & Kylee Van Horn 30.06.2026 55min

  Electrolytes have become one of the most heavily marketed areas of modern sports nutrition and wellness. What was once a relatively specific tool for certain endurance athletes has increasingly been reframed as an everyday requirement for hydration, energy, focus, productivity, and general health optimisation. But how much of this messaging is grounded in physiology, and how much is an example of industry taking a real mechanism and extending it far beyond the evidence? In this episode, we examine why many common use cases are unlikely to require an electrolyte product. Along the way, we explore how wellness marketing, biohacking culture, diet communities, and social media narratives can turn narrow sports nutrition applications into broad claims that many people come to accept as true. To discuss this topic, Danny is joined by Zoe Rom, a science and environmental journalist,  and Kylee Van Horn, a sports dietitian, to discuss how these claims are shaped by marketing, culture, and the attention economy. Timestamps: [04:00] Interview start [07:03] Wellness industry rebrand [09:16] Electrolytes 101 [16:02] Fear marketing and vague symptoms [22:50] When athletes actually need them [28:19] Salt fix and anti science narratives [33:53] Keto biohacking and identity [43:42] How to evaluate your need [48:43] Who should skip electrolytes Links: Go to episode page Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Your Diet Sucks podcast Fly Nutrition – Endurance Sports Nutrition
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  SNP51: Understanding Blood Glucose Reponses 23.06.2026 13min

  This is a Premium-exclusive episode. Go to the Premium feed to listen. Or subscribe to Premium. Blood glucose is easy to measure, but not always easy to interpret. This Premium-only episode brings together insights from several previous guests to examine blood glucose responses in more detail. We discuss the misuse of clinical thresholds, the difference between OGTT results and free-living CGM data, and whether "flatter" glucose curves are actually better in normoglycemic people. The episode also covers when repeated high glucose excursions may be worth investigating, how sugar intake should be interpreted in context, and why skeletal muscle and exercise play such an important role in glucose regulation. Overall, the aim is to clarify what glucose responses can tell us, what they cannot tell us, and how to avoid pathologizing normal physiology. Links:  Go to episode page Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course
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  #610: Rock, Paper, Salmon – Errors in Interpreting Food Substitution Models 16.06.2026 57min

  When considering the health impact of foods, it is important to consider "compared to what?". Increasing the amount of a certain food or nutrient in the diet, typically implies a displacement of another. While comparisons are more obvious in trials, in epidemiology food substitution models can be useful to help us determine the health effects of increasing/decreasing intake of a food, food group or nutrient. However, these models are often misinterpreted and miscommunicated as if they are a game of "rock, paper, scissors", where one food beats another, and the losing food must be removed from the diet or considered harmful to health. In this episode we discuss the problem of treating substitution analyses as food-ranking contests, rather than context-dependent comparisons shaped by the comparator, the unit of substitution, the baseline diet, and the outcome being studied. Timestamps: [01:30] Misuse of "compared to what?" [06:39] What substitution models do [10:43] Specified vs unspecified substitution [16:57] Why the units used matter [26:45] Example: organic vs conventional produce [31:22] When substitutions are useful [34:35] If legumes beat fish, does that mean fish intake should be zero? [44:31] Naive vs bias-adjusted: artificial sweeteners case study [49:14] Checklist: how to interpret food substitution analyses Links: Go to episode page (all study references linked) Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Subscribe to Alinea Nutrition Education Hub Enroll in the next cohort of our Applied Nutrition Literacy course Episode #472: Compared To What? Episode #589: Causal Inference in Nutrition Science – Daniel Ibsen, PhD
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  #609: Unprocessed Red Meat & Cancer Risk 09.06.2026 1h 9min

  Unprocessed red meat and cancer risk remains one of the most debated topics in nutrition science, partly because the evidence is often presented in overly simplistic terms. The key question is not whether to adopt a vague "balanced" position on red meat, but whether the evidence clearly identifies intake levels at which colorectal cancer risk increases and whether controlled human trials support plausible mechanisms for that risk. A second issue is whether claims that fibre, vegetables, or an otherwise "healthy diet" can neutralise high red meat intake are actually supported by the mechanistic evidence, or whether they overstate what dietary context can plausibly offset. In this episode, Danny and Alan examine the evidence base by moving beyond the usual epidemiology-only debate. They discuss why regional intake patterns and dose thresholds matter, then explore controlled human feeding studies showing how higher red meat intake can increase endogenous N-nitroso compound formation, faecal water genotoxicity, and other mechanistic biomarkers linked to colorectal carcinogenesis. Timestamps: [01:11] Defining the exposure and outcome [02:34] Carcinogen labels explained [07:54] Epidemiology and dose thresholds [14:04] Interpreting null findings [19:09] Bingham 1996 nitroso study [25:20] Hughes dose response trial [33:49] Cross 2003 heme iron mechanism [42:55] Fecal water genotoxicity [55:42] Tumor mutational signatures [59:38] What we can conclude now [01:04:10] Practical intake recommendations [01:08:41] Key ideas segment (premium-only) Links: Go to episode page (includes links to studies mentioned) Subscribe to Sigma Nutrition Premium Join the Sigma newsletter for free Enroll in the next cohort of our Applied Nutrition Literacy course
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  #608: Performance Nutrition in Elite Rugby – James Morehen, PhD 02.06.2026 1h 8min

  Performance nutrition in elite sport is often discussed in terms of meal plans, supplements, and macronutrient targets. However, effective practice in professional environments depends just as much on education, trust, communication, and the ability to translate scientific principles into decisions athletes can act on under real-world constraints. In this episode, Dr James Morehen discusses his work across elite rugby, football, and combat sports, with particular attention to the demands of professional rugby. The conversation explores how practitioners support athletes in a high-impact collision sport, including fuelling for training and match play, managing body composition without reducing athletes to arbitrary numbers, addressing recovery from muscle damage and injury, and developing practical systems around game-day nutrition. The episode also provides insight into the realities of building a career in performance nutrition, including the importance of applied experience, interdisciplinary collaboration, and learning how to coach athletes rather than simply prescribe to them. Timestamps: [03:31] Interview starts [10:26] Educating athletes on nutrition [13:55] Breaking into elite sport [26:26] Physiological demands of rugby [30:53] Energy needs and timing [38:28] Body composition measurements: utility? [46:16] Game day fuelling strategy [01:07:09] Key ideas (premium-only) Links: Go to episode page Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course James' Instagram: @morehenperformance James' LinkedIn: Dr. James Morehen Related episodes: #573: A Philosophy of Elite Performance Nutrition – Daniel Davey #286: Fuelling Elite Sport – James Morton, PhD #506: Sports Nutrition: Translating Research to Practice – Andreas Kasper, PhD
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  #607: Gut Health & Microbiome Testing: What Evidence Do We Actually Have? – Emily Leeming, PhD 26.05.2026 50min

  Gut health has become a major focus in nutrition, medicine, and consumer wellness, but the term is often used loosely. Claims about microbiome testing, probiotics, fermented foods, fibre, and "boosting" the gut microbiome are now common, yet the evidence behind these claims varies substantially. In this episode, Dr. Emily Leeming examines what gut health actually refers to, why it cannot be reduced to the microbiome alone, and where current microbiome science is being applied before it is ready. The discussion covers the limits of commercial stool testing, the difficulty of defining a healthy microbiome, and the practical strategies most strongly supported by current evidence. Timestamps: [02:48] Interview start [04:17] Defining gut health [09:03] What is a "healthy microbiome"? [15:25] Microbiome testing - any clinical utility? [24:08] Interpreting microbiome studies [34:39] "30 plants a week" is not evidence-based [39:53] Serotonin and gut brain [45:34] Fiber research frontier Links/Resources: Go to episode page (w/ links to mentioned studies) Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Dr. Leeming's newsletter: Second Brain
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  PMOS (PCOS) and Diet: What Can Nutrition Realistically Do? - SNP#50 21.05.2026 19min

  In this episode, we examine what nutrition can realistically do in the condition historically known as PCOS, now renamed polyendocrine metabolic ovarian syndrome, or PMOS. We begin by explaining why the name change matters: the condition is not defined by ovarian cysts, but is better understood as a broader endocrine-metabolic and ovarian syndrome involving insulin resistance, androgen excess, ovulatory dysfunction, metabolic risk, and psychological burden. We then assess the nutrition evidence, including energy restriction, weight loss, carbohydrate quality, glycaemic index and load, protein intake, fat quality, appetite regulation, fertility outcomes, and phenotype differences. Rather than seeking a single "PCOS diet", the episode asks which dietary features may plausibly help, how strong the evidence is, and where uncertainty remains. This is a Premium-exclusive episode. To listen to the full episode, subscribe to Premium. Links:  Go to episode page and resources Subscribe to Sigma Nutrition Premium Join the Sigma newsletter for free
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  #606: Practical Nutrition Strategies for Fat Loss – Luke Hanna 19.05.2026 41min

  Body composition goals, particularly bodyfat loss, are among the most common reasons people seek support from a nutritionist or health and fitness professional. While the principles are well established, the challenge is helping individuals apply them consistently in real-world conditions. Many people struggle due to hunger, unrealistic expectations, emotional eating, inconsistent routines, or overly restrictive dieting approaches. These challenges can make fat loss difficult to sustain, even when someone understands what they "should" be doing. In this episode,  Luke Hanna discusses practical strategies for improving body composition, including food diaries, energy-density manipulation, preloads, mindful eating, and realistic goal-setting. The discussion emphasizes identifying individual barriers, collaborating with clients, and building repeatable behaviours that support both fat loss and long-term maintenance. Luke Hanna holds a Master's degree in Obesity and Clinical Nutrition from University College London and a degree in Sport and Exercise Science from the University of Portsmouth. He currently works as a nutrition coach and personal trainer. Timestamps: [03:15] Interview [05:39] Client assessment basics [11:59] Alternatives to tracking [13:57] Volume eating [18:56] Preloads before meals [22:25] Snacking and hunger types [26:44] Habits and food environment [30:40] Managing expectations [33:51] Transition to maintenance [39:09] Key ideas (premium-only) Links: Go to episode page (with resources) Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Instagram: @lukehannanutrition
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  #605: Fasting, Nutrient Timing & CGMs: Interpreting the Evidence – Prof. James Betts 12.05.2026 56min

  Fasting, nutrient timing, chrono-nutrition, and continuous glucose monitoring are all topics that have generated substantial interest, but they are also areas where exaggerated claims can easily outpace the underlying evidence. In many cases, tentative hypotheses are presented as if they were already well-established conclusions, despite the fact that the research base is often more mixed and context-dependent than popular narratives imply. It is one thing for an idea to appear biologically coherent. It is another for that idea to translate into meaningful, reliable effects in real-world interventions. In this episode, Professor James Betts discusses how to think clearly about these topics, why common errors in interpretation can lead to overstated conclusions, and what is required to properly evaluate whether an observed effect reflects a true intervention effect rather than baseline differences, inappropriate comparisons, within-group changes, or mechanistic signals being mistaken for meaningful health outcomes. Timestamps: [04:24] Background into Prof. Betts' research [07:28] Evidence in fasting research over past 5-6 years [10:15] Hype vs evidence in intermittent fasting [16:44] Spotting spin in study conclusions [17:31] Common statistical red flags [24:45] Methods matter in fasting trials [31:10] Exercise nutrient timing [38:32] CGMs what they measure, misuse and patterns [53:59] Key ideas (premium-only)   Links: Go to episode page & resources (study links, bio, etc.) Join the Sigma newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course
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  #604: How To Interpret Nutrition Research – David Allison, PhD 05.05.2026 52min

  How should we decide what counts as trustworthy evidence? Scientific rigor is not a single characteristic of a study, but a chain of decisions made from the moment a question is conceived to the point at which findings are communicated to the public. Errors can occur at every stage: the question may be ill-posed, the design may be incapable of answering it, the measurements may be weak, the analysis may be inappropriate, the interpretation may overreach, and the public-facing communication may become distorted. In this episode, Dr. David Allison, PhD discusses the deeper methodological issues that shape the field's conclusions. The discussion moves from the philosophy of scientific inquiry to the practical realities of study design, statistical analysis, interpretation, and dissemination. Timestamps: [03:30] Interview start [06:17] What is true scientific rigor? [10:06] Study design and analysis problems in nutrition [12:56] The DINS error [14:14] Conflation of heterogeneity in response vs. in outcomes [17:31] Misunderstanding of p-values and hypothesis testing [27:01] Incorrect labelling of "responders" and "non-responders" [34:49] Errors related to analysis of secondary outcomes [45:01] How can nutrition science improve as a field? [51:30] Key ideas segment (Premium-only) Links: Go to episode page (with list of episode resources) Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course