Libsyn Directory

#589: Causal Inference in Nutrition Science – Daniel Ibsen, PhD

Release Date: 12/30/2025

#589: Causal Inference in Nutrition Science – Daniel Ibsen, PhD

Sigma Nutrition Radio

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 imperfectly, and we can’t easily run long-term diet experiments on people. Dr. Ibsen explains how embracing concepts like food substitution analysis, the “target trial” framework, and...

#588: Menstrual Cycle “Syncing”: Do the Claims Hold Up to Evidence? – Expert Panel

Sigma Nutrition Radio

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. But how much of that is actually grounded in evidence? In this episode, the conversation tackles those debates head-on, exploring what we truly know about female physiology, adaptation, and...

#587: How Should Nutrition Be Taught in Medical Training? – Akash Patel

Sigma Nutrition Radio

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 heavily to morbidity and healthcare costs, the conversation highlights a pivotal push to better equip physicians in nutritional knowledge and counseling. Patel’s work comes at a turning point: there...

#586: The Manufactured Collapse of Expertise

Sigma Nutrition Radio

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 expertise as a feature, not a bug. They claim that those that were conventionally seen as domain experts are either brainwashed, lazy in their thinking, or outright corrupt. And the solution is instead...

SNP46: Reviewing Six Key Insights from the Year’s Conversations

Sigma Nutrition Radio

This is a Premium-exclusive episode of the podcast. To listen to the full episode you need to be subscribed to . 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, emerging evidence, and shifts in understanding from the past year. Across topics such as dietary guidelines, ultra-processed foods, sleep, metabolism, environmental exposures, and the psychology of eating, this review...

#585: Why We Think Poorly: Reason, Emotion, and Evidence-Based Reasoning

Sigma Nutrition Radio

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 practice means, how domain expertise matters, and how factors like identity, beliefs, and emotions can derail objective reasoning. Timestamps [02:56] Dr. David Nunan on evidence-based medicine...

#584: EAT-Lancet: Does the Planetary Health Diet Improve Human Health?

Sigma Nutrition Radio

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...

#583: Ultra-Processed Foods & Fixing the Food Environment – Kevin Hall, PhD

Sigma Nutrition Radio

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...

SNP45: Antioxidants – What You Need To Know

Sigma Nutrition Radio

This is a Premium-exclusive episode of the podcast. To listen to the full episode you need to be subscribed to . 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...

#582: GLP-1 Agonists: Side Effects, Management and Diet – Dr. Spencer Nadolsky

Sigma Nutrition Radio

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 represent a paradigm shift in obesity management. Importantly, the conversation addresses practical aspects of using these drugs, including managing their side effects and optimizing...

More Episodes

Nutrition science has unique challenges – diets are complex, people self-report their food intake imperfectly, and we can’t easily run long-term diet experiments on people. Dr. Ibsen explains how embracing concepts like food substitution analysis, the “target trial” framework, and objective dietary assessment can strengthen evidence.

The episode centers on methodological insights that make nutrition research more reliable and actionable. Key themes include defining dietary comparisons explicitly (the “compared to what?” question), considering people’s starting diets, and using causal inference techniques to design better studies.

Daniel B. Ibsen is an epidemiologist and nutritional scientist whose work bridges rigorous causal inference methods with real-world diet and cardiometabolic disease research. He is an Associate Professor at Aarhus University, Denmark.

Timestamps

[00:13] Introduction to the topic
[03:23] Interview start
[08:02] The importance of asking the right questions in nutrition science
[22:18] Understanding causal inference in nutrition
[28:58] Challenges and approaches in nutrition epidemiology
[32:07] Mimicking dietary interventions in studies
[32:55] Target trial framework
[39:52] Objective vs. subjective dietary assessment
[47:01] Why causal effects of ultra-processed foods cannot be identified

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