The Proof

Dr. Leigh Baxt, a drug development expert, deconstructs the peptide boom sweeping wellness culture. She explains what peptides actually are, how the FDA drug development process works, why most compounds fail to become medicine, and why the claims circulating online far outpace the evidence. The episode separates approved peptide drugs from unregulated online products and explores the critical gap between promising lab results and proven human safety.

Microbiome scientist Dr. Suzanne Devkota unpacks what a healthy gut ecosystem really looks like — diversity, fiber, fermented foods, probiotics, Akkermansia, short-chain fatty acids, and why most stool tests are misleading.

Dr. Walter Willett untangles decades of confusion around saturated fat, seed oils, dairy, eggs, and plant protein. What a truly healthy dietary pattern looks like when you consider both human health and planetary health.

Mayo Clinic oncologist Dr. Dawn Mussallem shares her extraordinary personal journey — surviving stage 4 cancer, heart failure, and a heart transplant — and the science of lifestyle interventions in cancer survivorship.

Dr. Jessica Knurick examines the systems influencing American health — the gap between individual choices and public health realities, the rise of MAHA, and why many proposed solutions fail to address the real drivers of chronic disease.

Dr. David Katz examines the 2025 US Dietary Guidelines, analyzing where the final recommendations align with the Dietary Guidelines Advisory Committee's evidence review and where they diverge, particularly on ultra-processed food language.

Dr. Inigo San Millan — coach to Tour de France champion Tadej Pogacar — explains the metabolic science behind Zone 2 training, why mitochondrial dysfunction is the root of metabolic disease, and how to structure a cardio program for longevity.

Vascular medicine specialist Dr. Dan Soffer explains why people with 'perfect' risk factors still have heart attacks — the role of Lp(a), residual inflammatory risk, and the limitations of standard risk assessment.

NIH researcher Dr. Kevin Hall explains what controlled feeding studies reveal about why people eat 500+ more calories per day on ultra-processed diets, and why the 2025 US Dietary Guidelines avoided using the term 'ultra-processed.'

Master lipidologist Dr. Thomas Dayspring explains why LDL particle number matters more than LDL cholesterol concentration, when medication is necessary, and why heart disease can happen even when standard lipid panels look normal.

Solo episode distilling 100+ pages of the latest European (ESC 2024) and American (ACC/AHA 2025) blood pressure guidelines into a practical framework. Why blood pressure is the most important modifiable risk factor for cardiovascular disease.

Emory University preventive cardiologist Dr. Laurence Sperling on how to detect heart disease before symptoms appear — coronary calcium scores, advanced lipid testing, optimal blood pressure targets, and why lifestyle modification is the first prescription.

NHS GP and culinary medicine pioneer Dr. Rupy Aujla discusses optimal protein intake for aging, the connection between gut health and systemic inflammation, and practical cooking strategies for a nutrient-dense diet.

Simon Hill walks through his comprehensive bloodwork — 100+ biomarkers and biological age testing — revealing surprising findings and sharing a practical framework for interpreting health metrics.

Data scientist Dr. Hannah Ritchie uses data from Our World in Data to clarify what's actually driving climate change, the real impact of food choices, and why imperfect environmental solutions still matter.

Naturopathic doctor Dr. Matthew Nagra reviews the evidence on butter versus plant oils (olive, canola, soybean) for cardiovascular health and all-cause mortality, challenging claims that butter is benign or that seed oils are harmful.

Simon Hill provides three key protein takeaways from a Harvard and Tufts University study on protein intake and healthy aging, addressing Layne Norton's interpretation and the plant vs. animal protein question.

Yale neurologist and professional skeptic Dr. Steven Novella explains how to identify health misinformation, why scientific humility is more powerful than absolute certainty, and the psychology that makes us vulnerable to pseudoscience.

Exercise scientist Drew Harrisberg distills the Zone 2 evidence into a practical 3-day cardio program for longevity. Shares lessons from managing Type 1 diabetes through exercise and lifestyle optimization.

Stanford nutritional scientist Prof. Christopher Gardner discusses the Stanford twins study — identical twins randomized to vegan vs. omnivore diets for 8 weeks — and what it reveals about the role of genetics vs. diet quality in health outcomes.

Simon Hill answers listener questions on the carnivore diet, longevity foods, his daily supplement stack, self-improvement practices, and how to evaluate conflicting nutrition advice.

NIH researcher Kevin Hall presents his landmark research on ultra-processed foods: the first randomized controlled trial showing that UPF consumption leads to overeating and weight gain independent of macronutrient composition.

OB-GYN Dr. Jen Gunter debunks widespread misinformation about menopause, hormone replacement therapy, vaginal health products, and supplements marketed to women. A masterclass in evidence-based women's health.

Solo deep dive into olive oil — its role in longevity, impact on chronic disease risk, quality factors, and the science behind polyphenols and monounsaturated fats. Independently produced with no industry funding.

NYU internist Dr. Michelle McMacken cuts through the saturated fat debate, explaining why the 'butter is back' narrative is misleading, how LDL drives atherosclerosis, and why Paleo and Keto claims about saturated fat safety don't hold up.

Solo episode on why diets fail and what evidence-based weight loss actually looks like — caloric density, protein leverage, sleep, resistance training, and why GLP-1 drugs don't replace lifestyle change.

Harvard epidemiologist Walter Willett examines the 2025 U.S. Dietary Guidelines: where they align with science, where they diverge due to industry lobbying, and why the guidelines have been watered down over decades.

Dr. Satchin Panda from the Salk Institute explains how circadian rhythms regulate metabolism, why when you eat is as important as what you eat, and the optimal eating window for metabolic health.

Stanford nutrition scientist Christopher Gardner presents the DIETFITS trial: the largest diet comparison study ever conducted. The surprising finding: neither low-fat nor low-carb was superior. Diet quality trumped macronutrient ratio.