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 health-conscious folks about its ability to improve markers like VO2 max and mitochondrial function, which are associated with better health outcomes and longevity.

Prof. Brendon Gurd, an exercise physiologist at Queen’s University, is the co-author of a recent review published in Sports Medicine that examined some of the claims made around zone 2 training and health in the general population.

This episode looks at whether the evidence truly supports Zone 2 as a uniquely effective training zone or if this hype has outpaced the research. These insights help professionals and individuals make evidence-based recommendations and avoid unintended negative consequences of following certain ideas.

About The Guest

Dr. Brendon Gurd is a Professor in the School of Kinesiology and Health Studies at Queen’s University, where his research focuses on exercise physiology and skeletal muscle adaptation. His work explores how different intensities and types of exercise influence mitochondrial content and function in muscle tissue, with the goal of understanding how to optimize health and performance through training.

• [03:23] Discussion with Professor Brendan Gurd
• [05:56] Zone two training: Mechanisms and misconceptions
• [10:56] Practical applications and recommendations
• [22:16] Research gaps and future directions
• [35:47] Key ideas segment (Sigma Nutrition Premium)

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• List of Sigma's Recommended Resources
• Review paper: Storoschuk et al., 2025 – Much Ado About Zone 2: A Narrative Review Assessing the Efficacy of Zone 2 Training for Improving Mitochondrial Capacity and Cardiorespiratory Fitness in the General Population
• Lecture Slides: Prof. Brendon Gurd – Is Zone 2 the optimal intensity for inducing mitochondrial adaptation?

Fructose has often been labeled a uniquely damaging nutrient, blamed for obesity, diabetes, and other metabolic diseases. But does fructose truly have unique harmful effects or are the risks associated with it related to context and quantity?

The episode explores how fructose is metabolized in the body, why it gained a reputation for being problematic, and what the scientific evidence says about fructose in our diets. You will gain insight into why fructose was singled out in the past (e.g., its unique pathway in the liver and lack of insulin response), and how newer studies put those concerns into context.

It covers important nuances for practitioners and health-conscious individuals, especially given public confusion and fear around fructose (even in fruit).

Dr. Scott Harding, Ph.D., is an Associate Professor of Nutritional Biochemistry in the Department of Biochemistry at Memorial University of Newfoundland. His research explores the complex interactions between diet, metabolism, and chronic disease, with a particular emphasis on the metabolic effects of dietary sugars (especially fructose), the role of fats and phytosterols in lipid metabolism, and how public health policies like sugar taxation influence population health outcomes.

• [02:58] Dr. Harding’s academic background
• [08:45] Fructose metabolism in detail
• [12:51] Fructose in diet and public health
• [23:07] Current research
• [29:53] Identifying biomarkers for fructose overconsumption
• [31:12] Fructose impact on health
• [40:58] The food matrix
• [45:10] Personalized nutrition and future research directions
• [54:06] Key ideas segment (premium-only)

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• Related podcast episodes: #476, #468, #155
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Vitamin A is often one of the less-discussed micronutrients in relation to bone health, taking a back seat to nutrients like calcium and vitamin D. Yet this fat-soluble vitamin plays a fundamental role in skeletal development, remodeling, and mineral homeostasis. It influences gene expression in both osteoblasts and osteoclasts, and contributes to the regulation of bone turnover throughout the lifespan.

But what makes vitamin A particularly interesting, and controversial, is that its effects on bone appear to follow a double-edged pattern. While it’s essential for bone formation, several large epidemiological studies have suggested that chronically high intakes of preformed vitamin A may actually increase the risk of osteoporosis and fracture, especially when consumed as retinol from supplements or high-liver diets. And yet, the picture is not so clear-cut.

This raises compelling questions:

• Is the concern over vitamin A and bone health justified, or is it a case of context-dependent risk?
• Can vitamin A, when combined with adequate levels of D and K, actually support bone strength?
• And are there thresholds above or below which risk increases?

In this episode, we explore the human evidence on vitamin A and skeletal health, looking not only at fracture outcomes and bone mineral density data, but also at nutrient interactions, mechanistic plausibility, and the implications for supplement use in well-nourished populations.

Note: This is a Premium-exclusive episode, so you will only hear a preview on this public feed.

• [00:23] Vitamin A and bone health: an overview
• [02:50] Forms of vitamin A: retinol and carotenoids
• [04:16] Mechanisms of vitamin A in bone physiology
• [17:52] Nutrient interactions: vitamin A, D, and K
• [31:03] Practical takeaways and recommendations

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The idea that saturated fat might be harmful to our health has sparked controversy for decades. In recent years, counter-narratives have surged: suggesting that concerns over saturated fat were overblown, that LDL cholesterol doesn’t matter, or that the original diet-heart hypothesis has been debunked. These claims have become especially popular in online wellness spaces and certain dietary communities, often wrapped in compelling but misleading rhetoric.

So what does the best available evidence actually say? And how should we think about saturated fat, LDL cholesterol, and cardiovascular risk in the current day?

In this wide-ranging interview, originally recorded for the Chasing Clarity podcast, Alan and Danny explore the scientific consensus around saturated fat’s impact on blood lipids, why LDL and apoB are central to atherosclerotic disease, and how dietary patterns can meaningfully reduce risk.

Importantly, they also address some of the most persistent myths and half-truths that fuel confusion, from flawed interpretations of the Seven Countries Study to misrepresentations of newer meta-analyses.

• [03:41] How do we know saturated fat impacts LDL-C?
• [05:28] Metabolic ward studies and key findings
• [11:13] The Keys equation and subsequent research
• [17:17] Epidemiology and long-term studies
• [31:48] The Seven Countries Study
• [44:25] Understanding the impact of saturated fat on blood lipids
• [47:23] Historical and research perspectives on saturated fat
• [50:43] Practical dietary strategies for improving blood lipids
• [53:48] The Portfolio Diet and other dietary interventions
• [58:07] The role of pharmacology in managing blood lipids
• [01:00:58] Addressing misconceptions and common claims
• [01:13:57] Key ideas segment (premium-only)

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• Alan Flanagan’s Alinea Nutrition Education Hub
• Related episodes to add to your podcast queue: 532, 525, 515, 493, 481, 439

To what extent can maternal nutrition during pregnancy influence a child’s later cognitive or behavioural development?

While genetic and environmental factors are known to contribute to neurodevelopmental outcomes such as ADHD and autism, growing attention is being paid to the potential role of prenatal exposures, including dietary patterns. Yet, evidence in this area remains limited, and causality is difficult to establish.

One recent study aimed to explore this question by analysing how maternal diet quality during pregnancy (specifically, adherence to a Western-style dietary pattern) related to neurodevelopmental outcomes in children assessed clinically at age 10.

In this episode, Dr. David Horner discusses the findings from this prospective cohort study, the use of metabolic markers to complement dietary data, and the implications for future research into modifiable prenatal risk factors.

About The Guest

Dr. David Horner is a researcher in maternal nutrition and cardiometabolic health, based at the University of Copenhagen, Denmark. He is also a qualified medical doctor from Queen’s University of Belfast.

His research is driven by a keen interest in modifiable determinants of health, aiming to better understand and improve health outcomes.

Having worked as a medical doctor for 2 years in the UK, in 2017 Dr. Horner then moved to Copenhagen, where he completed a Master’s in Global Health and a PhD examining the impact of maternal dietary patterns during pregnancy on child health.

• [02:47] Introduction to the study
• [07:08] Strengths and findings of the study
• [21:17] Genetic factors and gene-environment interactions
• [25:42] Metabolomics and potential mechanisms
• [30:12] Interpreting the study’s findings
• [38:03] Future research directions
• [42:50] Key ideas segment (Sigma Nutrition Premium)

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• Email: david.horner@dbac.dk
• Study: Horner et al., 2025 – A western dietary pattern during pregnancy is associated with neurodevelopmental disorders in childhood and adolescence
• David’s LinkedIn post about the study (with discussion in the comments)

For decades, dietary guidelines—and the Food Pyramid in particular—have been at the center of heated debates and considerable controversy. These guidelines have often been accused of being influenced by industry interests, oversimplifying nutritional nuance, or even directly contributing to rising obesity and metabolic disease rates.

In this episode, we critically assess common claims surrounding the Food Pyramid, including whether it was truly shaped by vested industry interests, if it encouraged harmful dietary shifts toward excessive carbohydrate and sugar consumption, and whether the subsequent health outcomes seen at the population level can be fairly attributed to these guidelines.

Additionally, we evaluate the role of the sugar industry in funding key studies and publications, examining the implications such conflicts of interest may have had on nutritional science.

Drawing on historical context, rigorous examination of scientific evidence, and an evaluation of how nutritional recommendations have evolved, this discussion aims to clarify misunderstandings, highlight legitimate criticisms, and separate fact from persistent myths regarding dietary guidance and its implications for health.

• [01:37] Common claims and narratives
• [03:15] Historical context of dietary guidelines
• [21:57] Sugar industry influence on dietary research
• [36:17] The mcgovern report
• [40:49] Misconceptions about dietary guidelines
• [44:28] Changes in food supply and consumption
• [58:15] Critiques and conflicts of interest
• [01:06:47] Key ideas segment (Premium-only)

Links & Resources

• Go to episode page (with linked resources)
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• Alan Flanagan’s Alinea Nutrition Education Hub
• MASS Research Review - latest training and nutrition research relevant to strength trainees
• Examine is the best online database for looking at the evidence of diets, foods and supplements on a range of health outcomes.

Inflammation has become a nutrition buzzword, often used in extreme or misleading ways. This episode aims to clarify what inflammation is, how it relates to diet and health, and whether specific foods truly provoke inflammatory responses in the body.

The episode provides a nuanced, evidence-based look at inflammation and diet. It explains the difference between acute and chronic inflammation, outlines the role of chronic low-grade inflammation in disease, and emphasizes that overall dietary patterns – rather than any single food – are what influence our inflammatory status.

Commonly demonized foods (such as sugar, wheat, and dairy) are scrutinized, and the conversation debunks myths about them being uniformly “inflammatory.” In this episode, Danny takes a look at what the scientific evidence actually shows about anti-inflammatory diets.

Note: This is a Premium-exclusive episode.

• 01:06 Understanding Inflammation: Basics and Biomarkers
• 04:02 Acute vs. Chronic Inflammation
• 14:21 Biomarkers of Inflammation
• 22:51 Dietary Patterns and Inflammation
• 34:53 Specific Foods and Nutrients Impacting Inflammation
• 47:01 Practical Takeaways for an Anti-Inflammatory Diet
• 51:30 Conclusion

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• Related podcast episodes:
  • 329: Diet & Inflammation
  • 353: James Hébert, ScD – Dietary Inflammatory Index
• Sigma Statement: Nutrition & Immune Function
• The Dietary Inflammatory Index (DII) – Hébert et al., 2019

GLP-1 receptor agonists have changed the landscape of obesity treatment, offering levels of weight loss once thought unattainable without surgery. But what happens after the weight is lost? And can we really talk about success without talking about maintenance?

While much of the public discourse fixates on dramatic weight loss numbers, the harder question is what comes next. Can lifestyle interventions alone sustain weight loss after GLP-1 cessation? How do metabolic adaptations and behavioral relapse factor in? And what does the data actually show about relapse rates, nutritional adequacy, and lean mass preservation when using these medications?

In this episode, Danny sits down with Tara Schmidt, dietitian at the Mayo Clinic, to examine the intersection of pharmacology and behavior in long-term weight management.

Tara Schmidt is a registered dietitian and an instructor of nutrition at Mayo Clinic. As the lead dietitian for the Mayo Clinic Diet, she provides guidance rooted in evidence-based principles. She hosts the Mayo Clinic On Nutrition podcast and co-authored The Mayo Clinic Diet: Weight Loss Medications Edition.

• [05:17] Understanding weight loss maintenance
• [08:44] Defining success in weight loss maintenance
• [11:54] Predictors of maintenance: self-monitoring and behavioral strategies
• [23:37] Pharmacological interventions: GLP-1 receptor agonists
• [31:06] Dietary considerations for those taking GLP-1 RAs
• [37:07] Addressing misconceptions about weight loss drugs
• [42:48] Final thoughts and takeaways
• [48:49] Key ideas (Premium-only)

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