Libsyn Directory

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

Release Date: 05/05/2026

#626: Practical Diet Considerations for Healthy Aging - Prof. Charlyn Black

Sigma Nutrition Radio

Living longer does not necessarily mean spending more years in good health. But how much of the decline we associate with aging is inevitable, and how much reflects disease, inactivity, and other potentially modifiable factors Nutrition presents a particular challenge in later life: energy requirements often fall, while the need for many nutrients remains unchanged or increases. How should we interpret claims about protein, plant-based diets, supplements, and bone health? To discuss this is Prof. Charlyn Black, a long-time health services and policy researcher at the University of British...

Can Micronutrient Supplements Help With Anxiety, Depression & Emotional Regulation? (SNP55)

Sigma Nutrition Radio

Can broad-spectrum vitamin and mineral supplements improve anxiety, depression or emotional regulation? In this Premium-exclusive episode, we examine three randomised, placebo-controlled trials from Professor Julia Rucklidge’s research group: NoMAD, investigating anxiety and depressive symptoms in adults; NUTRIMUM, examining depressive symptoms during pregnancy; and BEAM, studying irritability and emotional dysregulation in adolescents. These studies offer an opportunity to explore some central challenges in interpreting nutrition and mental health research. What does “faster...

#625: Does Changing the Microbiome Actually Improve Health? – Prof. Harry Sokol

Sigma Nutrition Radio

Claims about “improving the gut microbiome” are widespread, but what would improvement actually mean? How do we establish which microbial changes contribute to disease, and which simply reflect it? Research on bacterial metabolism of medications raises questions about how the microbiome might influence treatment efficacy and toxicity. What would it take to translate these findings into reliable tests and effective therapies? In this episode, gastroenterologist and researcher Prof. Harry Sokol examines these questions, discusses the development of Faecalibacterium prausnitzii as an...

#624: Can Athletes Eat for Performance and the Planet? – Peter Res

Sigma Nutrition Radio

Can an athlete reduce the environmental impact of their diet while still meeting the demands of training, competition and recovery? Peter Res argues that these aims can be compatible, provided dietary changes are planned around the athlete’s needs. The discussion looks at practical changes athletes can make to make their diets more environmentally sustainable. This includes tips on increasing the contribution of plant proteins, maintaining adequate energy intake, and making plant-rich eating practical within sporting environments. Timestamps [04:21] Peter Res’ background [05:22]...

#623: Testosterone Testing: What Do the Results Mean? When Does TRT Help? – Austin Baraki, MD

Sigma Nutrition Radio

Men commonly feel that if their testosteone isn’t “optimized” and high, they are missing out on greater health in a variety of ways. But what can a testosterone result actually tell us? How can results be interpreted with appropriate nuance that is needed? How low is low enough to be problematic? In situations where a test flags testosterone as low, there is a belief this means automatically starting testosterone replacement therapy. While TRT can be an excellent intervention in appropriate cases, when is it actually likely to benefit someone, and when is it not? For many people the...

#622: Body Composition Testing: Methods & Interpretation – Prof. Grant Tinsley

Sigma Nutrition Radio

Body composition testing is widely used in research, sport and clinical practice. But what are these methods actually measuring, and how much confidence should we place in the numbers they produce? In this episode, we examine the assumptions behind common approaches including DXA, bioelectrical impedance, and skinfold measurements. We discuss the distinction between accuracy and reliability, the value and limitations of repeated measurements, and how coaches, clinicians, researchers and individuals can select an appropriate method and interpret the data without overstating its precision....

#621: Hedonic Overeating, Food Wanting and Impact of Perception – Prof. Graham Finlayson

Sigma Nutrition Radio

Why do some foods feel difficult to stop eating, while others can be highly enjoyable without prompting the same tendency to overconsume? Answering this requires a clearer understanding of food reward, including the distinction between liking a food, wanting it, and perceiving it as easy to overeat. In this episode, we examine how nutritional composition, sensory characteristics, learned beliefs and the eating context may shape hedonic overeating. It also considers the limits of using broad food categories to explain complex eating behaviour. Discussing all this is Professor Graham Finlayson,...

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

Sigma Nutrition Radio

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...

#619: How Much Fish Should a Healthy Diet Contain?

Sigma Nutrition Radio

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...

#618: How Wellness & Optimisation Culture Can Commodify Science – Nick Tiller, PhD

Sigma Nutrition Radio

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...

More Episodes

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)
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Enroll in the next cohort of our Applied Nutrition Literacy course

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