Sigma Nutrition Radio

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 episo...

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...

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...

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 o...

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 p...

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 wo...

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 reduce...

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, ovu...

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 ove...

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 cont...

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 analys...

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 th...

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...

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...

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 compat...

"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...

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...

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...

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 regi...

Omega-3 fatty acids (particularly EPA and DHA) have a long history in nutrition and cardiovascular medicine, yet the clinical trial literature is often perceived as inconsistent. This episode examines why some randomized trials show clear benefit while others show null or mixed findings, and how differences in trial design, dose, population risk, and outcome selection can materially change what we...

Conversations about brain health have been dominated by a competing mix of fatalism and over-promising, with aging framed as inevitable decline and "brain optimisation" sold through weak evidence. So how should we think about cognition across the lifespan? In this episode, we explore the idea that neuroplasticity does not disappear in adulthood, but instead continues to respond, for better or wors...

This is a  Premium-exclusive episode  of the podcast. To listen to the full episode you need to be subscribed to  Sigma Nutrition Premium . This episode examines dietary fiber through the lens of a practical, clinically relevant question: if higher fiber intakes are consistently associated with reduced chronic disease risk, what intake level should we be aiming for to meaningfully improve health o...

Dr. José Areta and colleagues recently carried out a human intervention study examining how a pronounced, short-term energy deficit interacts with an aerobic training stimulus to shape endocrine, metabolic, and skeletal muscle proteomic adaptations. The core premise is that "low energy availability" is often discussed in a largely unidirectional risk framework, yet human physiology evolved under i...

While the term "hyperpalatable" has been used frequently for considerable time to refer to foods that are so appealing and tasty that they drive overeating, this term hasn't been well-defined nor has there been a universal standard for what it means. One researcher who set out to create an objective definition for hyper-palatable foods (HPFs) is Dr. Tera Fazzino. Using specific defined thresholds...

In this episode, the discussion turns to a deceptively simple question that sits at the centre of countless nutrition debates: how much protein do we actually need? On one side, there are confident claims that very high protein intakes are not just beneficial but essential for maximising strength, performance, and muscle mass. On the other, equally strong assertions that the current RDA is entirel...