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 proposed a mostly plant-based dietary pattern designed to improve population health while staying within planetary boundaries. But since then, new data have emerged—on nutrient requirements, disease risk, and environmental modelling—that complicate many of the original assumptions.

What does the updated evidence actually say about the health impacts of eating in line with this framework? How have the environmental projections changed? And what do these evolving targets mean for individuals, policymakers, and researchers trying to translate broad sustainability goals into practical dietary guidance?

These are some of the questions explored in this episode of Sigma Nutrition, which examines the 2025 EAT-Lancet update, its scientific foundations, and what it reveals about the intersection of nutrition, health, and planetary sustainability.

• [01:46] Focus on the 2025 EAT-Lancet report
• [02:27] Overview of the Planetary Health Diet
• [03:13] Comparing 2019 and 2025 reports
• [03:40] Dietary recommendations and nutrient targets
• [04:14] Health and environmental impacts
• [09:12] Scoring methods and dietary patterns
• [27:00] Mortality and chronic disease outcomes
• [40:01] Type 2 diabetes
• [44:13] Neuroimaging and cognitive outcomes
• [49:48] Conclusions and practical implications
• [58:55] Key ideas segment (Premium-only)

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  • Report: EAT-Lancet

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 palatability, the rate at which we consume them, or the broader environments that make them so accessible and appealing?

The debate around ultra-processed foods sits at the intersection of metabolic science, behaviour, and policy. It raises uncomfortable questions about how food systems evolved to prioritise convenience and profit, and what it might take to meaningfully change that trajectory.

In this episode, Dr. Kevin Hall joins the podcast to examine the evidence from controlled feeding studies and population research, exploring what we really know about ultra-processed foods, overeating, and how we might begin to fix the food environment.

• [04:24] Dr. Hall's background and career
• [06:47] Ultra processed foods and health
• [15:10] Mechanisms behind ultra processed foods
• [27:00] Healthy ultra processed foods: a possibility?
• [30:43] Minimizing ultra processed foods in different cultures
• [33:03] Policy and regulation for better food quality
• [44:26] The importance of pilot studies in policy implementation
• [49:10] Future of food and sustainable diets
• [51:50] Key ideas segment (Premium-only)

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  • @KevinH_PhD
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• Book: Food Intelligence: The Science of How Food Both Nourishes and Harms Us
• Previous episodes with Dr. Hall: #429, 376, 165, 88

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 this episode, Danny explores the true role of antioxidants in the body, challenging simplistic narratives. Are antioxidants magic molecules that single-handedly prevent aging and disease? Or is the reality more nuanced, with context and balance being key? We delve into these intriguing questions to clarify what antioxidants are, how they work, and what the current consensus tells us about using them for health.

Antioxidants are frequently credited as the reason why colorful fruits and vegetables are beneficial. Yet, as past Sigma episodes on polyphenols have noted, the benefits of those plant foods aren't primarily due to direct antioxidant effects.

Here we untangle common misconceptions (e.g., "antioxidants = health, always"), distinguish between different types of antioxidants, and explain why simply taking high-dose antioxidant supplements isn't a guarantee of protection – and in some cases might even backfire.

By the end, health professionals and science-savvy listeners will understand the diverse roles of antioxidants, the importance of balance, and how to apply this knowledge in practice.

• [01:27] Understanding antioxidants
• [04:19] The role of free radicals
• [08:43] Endogenous antioxidant systems
• [09:58] Dietary antioxidants
• [16:03] Polyphenols and their impact
• [24:28] Health benefits of polyphenols
• [27:39] Antioxidants in cognitive function
• [36:47] Practical takeaways on antioxidants

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