Sigma Nutrition Radio

Maintaining the ability to carry out everyday tasks and live independently is often described as a cornerstone of healthy ageing. But what actually happens to muscle strength, power, and functional ability as we get older? And how inevitable is their decline? At what point do changes in muscle function really begin to matter for day-to-day life? Is loss of strength an unavoidable consequence of ag...

Nutrient density refers to the concentration of vitamins and minerals in crops relative to their yield. There are widespread claims that today's fruits, vegetables, and grains contain fewer micronutrients than in decades past, often linked to modern farming practices or soil degradation. This issue is important because if staple crops become less nutritious, it could silently undermine dietary qua...

This is a  Premium-exclusive episode  of the podcast. To listen to the full episode you need to be subscribed to  Sigma Nutrition Premium . Recently we (Danny Lennon & Alan Flanagan) were invited to  'Processing the Evidence' , a "behind closed doors" workshop to discuss the latest scientific evidence on the role of processed foods in human health. The event was organized by Professors Ciarán Ford...

This episode explores how asking better questions and using stronger methods can resolve much of the confusion in nutrition science. Dr. Daniel Ibsen discusses why nutrition research often produces conflicting results and how careful methodological thinking can clarify true diet-disease relationships. Nutrition science has unique challenges – diets are complex, people self-report their food intake...

How much do hormonal fluctuations really influence performance and recovery? Should women be adjusting their training and nutrition based on the menstrual cycle? And do female athletes need different protein strategies or recovery protocols than men? These are questions that have fuelled countless online claims, from rigid "cycle syncing" programmes to supposedly gender-specific nutrition rules. B...

This episode centers on the critical gap in nutrition education within medical training and efforts to bridge it. Guest Akash Patel, a medical student who led a pilot nutrition curriculum, discusses why doctors receive little formal training in nutrition despite poor diet being a major driver of disease. With diet-related conditions (obesity, diabetes, cardiovascular disease, etc.) contributing he...

Never before has there been greater access to information about nutrition and health. But never before has there been such a low barrier to being seen as an "expert". There are large numbers of people getting information from, and basing their health decisions on, people who don't have direct expertise in the field in which they are talking about. Moreover, some promote the lack of domain expertis...

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, emerg...

We take a look at critical thinking in science and healthcare, examining how we often fall prey to cognitive biases, emotional reasoning, and flawed thinking. Drawing from six different experts in their respective fields, the episode explores why we sometimes believe we are being rational when in fact our conclusions aren't truly evidence-based. The discussion spans what genuine evidence-based pra...

How should we think about diets that claim to optimise both human and planetary health? Can a single "reference diet" really balance the complex trade-offs between nutrition adequacy, chronic disease prevention, and environmental sustainability? These questions have gained renewed attention with the release of the 2025 update to the EAT-Lancet Planetary Health Diet. The original 2019 report propos...

Ultra-processed foods have become central to the way we eat and to many of the challenges we face in public health nutrition. They dominate supermarket shelves, shape population diets, and often appear as the prime suspect in rising obesity and metabolic disease rates. But beyond the label itself, what exactly makes these foods problematic? Is it their nutrient composition, their texture and palat...

This is a  Premium-exclusive episode  of the podcast. To listen to the full episode you need to be subscribed to  Sigma Nutrition Premium . What exactly are "antioxidants," and why do they get so much hype? We often hear that blueberries, dark chocolate, and red wine are healthy because they're packed with antioxidants – but is the story really as simple as "more antioxidants = better health"? In...

GLP-1 receptor agonists have emerged as a groundbreaking tool in obesity treatment. In this episode, Dr. Spencer Nadolsky (an obesity specialist) explains how these medications are now yielding unprecedented weight loss outcomes in people with obesity.  The discussion centers on GLP-1 agonist drugs like semaglutide and tirzepatide: how they work, how much weight loss they can produce, and why they...

Public nutrition policy plays a critical role in shaping population health through laws, guidelines, and programs that influence what people eat. In this episode, Emily Callahan, an expert in nutrition policy, talks about why public nutrition policies often fall short and what "success" looks like. They discuss how evidence-based nutrition interventions can stall due to political or practical barr...

Sodium bicarbonate is one of the most consistently supported ergogenic aids in sports nutrition research, yet its underlying mechanisms and real-world applications remain widely misunderstood. More recent developments have focused on how to optimise both the timing and formulation of supplementation. The "individualised ingestion timing" approach has emerged as a practical strategy, recognising th...

In this episode, we explore the concept of chronotype, which reflects an individual's biological circadian timing and how it manifests in preferred sleep–wake patterns. Understanding chronotype is important because it differs from simple diurnal preference, which may be shaped by lifestyle or psychological factors rather than biology. We examine how chronotype is measured, from gold-standard labor...

Creatine is best known as a sports supplement for enhancing muscle strength and high-intensity performance. But could it also improve brain health and cognitive function? Or are such claims overhyped? If creatine can support brain health, it could have implications for aging, neurodegenerative diseases, concussion recovery, and mental fatigue. In this podcast episode, Professor Eric Rawson discuss...

Energy expenditure is one of the most fundamental yet often misunderstood aspects of human physiology. A central question is whether there is a ceiling to how many calories we can burn, and what happens when activity levels approach that limit. Grasping these dynamics is essential for health professionals and researchers, as energy balance directly influences body weight regulation, metabolic heal...

Recently a new trial was published in Nature Medicine comparing the effect of ultra-processed versus minimally processed diets. Specifically, the UPDATE trial compared these two diets in the context of a healthy dietary pattern (in line with the UK's EatWell Guide). This eight-week randomized, crossover trial generated a lot of discussion and was largely seen as being a really useful addition to t...

In this episode, Dr. Matthew Facciani explores how social psychology influences health beliefs and the spread of misinformation. The conversation delves into why people adopt certain nutrition or health beliefs so strongly, how identity and group membership shape our interpretation of evidence, and what makes us susceptible to false or misleading health claims. Dr. Facciani's interdisciplinary bac...

Dairy is often treated as a single food group, yet milk, yogurt, cheese, and butter can have very different effects on health. Some evidence links yogurt to favourable outcomes, while butter is known to raise LDL cholesterol. And then there's the paradox of cheese: high in saturated fat, but not consistently associated with higher heart disease risk. These complexities raise the question of whethe...

They're in our oceans, our air, our food, and now even in our bodies. Microplastics, once a distant environmental issue, have become a topic of urgent relevance in medicine, public health, and nutrition. The idea that tiny plastic particles are circulating through the food chain and accumulating in human tissues has sparked headlines, speculation, and concern. But how much of this fear is grounded...

In this episode, performance nutritionist Daniel Davey discusses how his approach to elite sports nutrition has evolved over his career. Davey reflects on his decade working with top Irish teams (Dublin GAA/football and Leinster Rugby) and how stepping away from those environments led him to rethink the role of a nutrition practitioner.  The central theme is a shift from a traditional prescriptive...

Nutrition science plays a pivotal role in shaping public health advice, but the influence of industry funding on research has become a pressing concern. In this episode we want to examine whether we can trust nutrition studies funded by food and beverage companies, and how you can discern study credibility.  The discussion is highly relevant in today's landscape, where conflicts of interest and bi...

In recent years "Zone 2 training" has gained immense popularity in fitness and health circles, often being proclaimed the "best" cardiovascular training for metabolic health.  Zone 2 training is sustained, low-intensity exercise below the lactate threshold that is commonly employed by many elite level endurance athletes, with a variety of proposed performance benefits. This led to interest from he...