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

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 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 Links/Resources: Go to the episode page (with links to mentioned studies) Join the Sigma email newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course