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SNP46: Reviewing Six Key Insights from the Year’s Conversations

Sigma Nutrition Radio

Release Date: 12/02/2025

#605: Fasting, Nutrient Timing & CGMs: Interpreting the Evidence – Prof. James Betts show art #605: Fasting, Nutrient Timing & CGMs: Interpreting the Evidence – Prof. James Betts

Sigma Nutrition Radio

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...

info_outline #604: How To Interpret Nutrition Research – David Allison, PhD show art #604: How To Interpret Nutrition Research – David Allison, PhD

Sigma Nutrition Radio

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...

info_outline #603: Should Dietary Fiber Be Considered Essential? – Andrew Reynolds, PhD show art #603: Should Dietary Fiber Be Considered Essential? – Andrew Reynolds, PhD

Sigma Nutrition Radio

Dietary fiber is widely recognized as an important component of a healthy diet, yet it is not typically classified as an essential nutrient. In this episode, Dr. Andrew Reynolds explores whether that distinction still holds, arguing that the traditional criteria used to define essentiality may be outdated when applied to modern nutrition science. The discussion moves beyond simply acknowledging the benefits of fiber and instead examines whether it meets the foundational requirements of an essential nutrient. This includes considering its physiological roles, the body’s inability to...

info_outline #602: Avoidant/Restrictive Food Intake Disorder (ARFID) – Megan Hellner, DrPH, RD & Katherine Hill, MD show art #602: Avoidant/Restrictive Food Intake Disorder (ARFID) – Megan Hellner, DrPH, RD & Katherine Hill, MD

Sigma Nutrition Radio

Avoidant/Restrictive Food Intake Disorder (ARFID) is an eating disorder diagnosis characterized by a persistent restriction or avoidance of food intake that results in clinically significant consequences (medical, nutritional, and/or psychosocial), but without the weight- and shape-driven psychopathology typical of anorexia nervosa and bulimia nervosa. In this episode, Megan Hellner and Katherine Hill outline how ARFID presents across the lifespan, why it is frequently missed in routine healthcare, and what an evidence-informed assessment and treatment pathway can look like in practice. A...

info_outline #601: Gallstones & Gallbladder Conditions: Impact of Diet – Angela Madden, PhD RD show art #601: Gallstones & Gallbladder Conditions: Impact of Diet – Angela Madden, PhD RD

Sigma Nutrition Radio

This episode examines what we actually know (and importantly, what we do not know) about diet in relation to gallstones and gallbladder conditions. Much of the public-facing guidance around gallstones focuses on “avoiding fatty foods”, yet Dr. Angela Madden explains that this long-standing practice sits on surprisingly weak direct evidence, particularly when judged against the standards typically expected for clinical dietary recommendations. A central theme is the need to separate two distinct questions: dietary factors that influence the risk of developing gallstones (prevention), versus...

info_outline Coevolution With Foods? Multivitamins? Eating Too Early? – Ask Me Anything (SNP49) show art Coevolution With Foods? Multivitamins? Eating Too Early? – Ask Me Anything (SNP49)

Sigma Nutrition Radio

In this episode, Danny answers questions submitted by Premium subscribers. Questions Answered in This Episode: [00:05:13] Is eating too early (relative to chronotype) metabolically problematic? [00:16:55] Can plant-based diets reverse cardiovascular disease? [00:32:54] Are multivitamins useful insurance, or a waste with a good diet? [00:44:56] Does coevolution with foods determine human compatibility and benefit? [00:56:25] How should consumers choose supplement formulations and brands? [01:04:46] Folate vs folic acid: differences and best choice for women of...

info_outline #600: Finite Knowledge, Infinite Ignorance show art #600: Finite Knowledge, Infinite Ignorance

Sigma Nutrition Radio

“The more we learn about the world, and the deeper our learning, the more conscious, specific, and articulate will be our knowledge of what we do not know, our knowledge of our ignorance. For this, indeed, is the main source of our ignorance — the fact that our knowledge can be only finite, while our ignorance must necessarily be infinite.” – Karl Popper To mark Sigma Nutrition’s milestone 600th episode (and 12-year anniversary), Danny and Alan examine several areas in which their views have changed, softened, strengthened, or remained stable over the lifespan of the podcast....

info_outline #599: Does Unprocessed Red Meat Increase Diabetes Risk? – Gil Carvalho, PhD MD & Mario Kratz, PhD show art #599: Does Unprocessed Red Meat Increase Diabetes Risk? – Gil Carvalho, PhD MD & Mario Kratz, PhD

Sigma Nutrition Radio

This episode examines whether unprocessed red meat has a causal role in (1) type 2 diabetes risk and intermediate measures of glucose intolerance (insulin resistance, beta cell dysfunction, glycemic markers) and (2) cardiovascular disease (CVD) risk. While there is commonly observed risk signal from observational cohorts, there exist short-term randomized controlled trials (RCTs) that show largely null effects on glucose homeostasis. This had led to differing opinions and interpretations of the evidence base. Some feel that in the context of an otherwise healthy diet, there isn’t much to...

info_outline #598: How Do Exercise & Diet Interact to Improve Glycaemic Control? – Jenna Gillen, PhD show art #598: How Do Exercise & Diet Interact to Improve Glycaemic Control? – Jenna Gillen, PhD

Sigma Nutrition Radio

This episode examines how exercise and nutrition interact to influence glycaemic control, with particular focus on the postprandial period (i.e., the hours after eating) and on “time-efficient” exercise strategies such as low-volume interval training. Dr. Jenna Gillen outlines the physiological basis for why muscle contraction can acutely reduce post-meal glucose excursions, why repeated sessions can accumulate into longer-term improvements in insulin sensitivity, and why the nutrition context (pre- and post-exercise feeding, carbohydrate availability, and energy balance) can meaningfully...

info_outline #597: Behavioral Psychology in Diet & Health Counselling – David Creel, PhD, RD show art #597: Behavioral Psychology in Diet & Health Counselling – David Creel, PhD, RD

Sigma Nutrition Radio

In clinical practice effective nutrition, exercise, and obesity care is rarely about identifying the single “best” plan on paper. Instead, sustainable change depends on behavioral psychology: understanding the person’s context, motivation, barriers, and patterns, then co-designing practical steps that can actually be implemented in real life. David Creel PhD, RD is a clinical psychologist and registered dietitian working in weight management at the Cleveland Clinic. Dr. Creel discusses how clinicians can bridge the gap between “optimal recommendations” and what is most likely to...

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This is a Premium-exclusive episode of the podcast. To listen to the full episode you need to be subscribed to Sigma Nutrition Premium.

Each year, the conversations on Sigma Nutrition Radio aim to examine the ideas that shape how we understand nutrition, health, and human behavior. This episode brings together the key insights from those discussions, revisiting the most important themes, emerging evidence, and shifts in understanding from the past year.

Across topics such as dietary guidelines, ultra-processed foods, sleep, metabolism, environmental exposures, and the psychology of eating, this review distills what the science actually shows and what remains uncertain.

Whether you have followed throughout the year or are tuning in for the first time, this episode provides a concise synthesis of what truly mattered and what these ideas imply for how we interpret nutrition science moving forward.

Timestamps

  • [02:23] Christopher Gardner, PhD – How dietary guidelines are shaped, misused, and what the evidence really supports.
  • [13:10] Marie-Pierre St-Onge, PhD – The bidirectional relationship between sleep quality, circadian timing, and diet.
  • [20:03] Duane Mellor, PhD – Rethinking ultra-processed foods: mechanisms, misconceptions, and policy realism.
  • [29:26] Samuel Dicken, PhD – The UPDATE trial and what nutrient-matched processing tells us about satiety and intake.
  • [35:37] Ian Mudway, PhD – Microplastics, pollution, and why evidence must outrun public fear.
  • [43:46] Martin Caraher, PhD – The financialization of food systems and its impact on inequality and diet quality.

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