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, mai...

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 therap...

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 me...

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 hed...

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 ...

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...

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 explo...

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 epis...

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:

1. Fiber: Independent effect or proxy for healthy foods?
2. Exposure frequency for matched dose of red meat<...

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...

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...

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 th...

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 interac...

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, Profe...

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 an...