The Proof

Dr Thomas Dayspring and Dr Dan Soffer, both Masters of the National Lipid Association, join Simon Hill to discuss why nearly all of us have atherosclerosis even when cholesterol is labeled normal. They debate whether ApoB is causal or just necessary, explain the misperception of 'normal' cholesterol, and outline practical tools like LDL-C years and the 2026 dyslipidemia guideline update. The conversation offers an honest look at how experienced clinicians weigh evidence when treating people who feel well.

Dr. Deborah Kado, a Stanford geriatrician and professor of medicine, joins Simon Hill to discuss what actually contributes to a long, well-lived life. They cover the rebranding of gerontology as 'longevity science,' the protective link between a positive attitude toward aging and lower dementia risk, and the critical importance of balance and power training for preventing falls and fractures. Kado addresses the widespread fear around osteoporosis medications triggered by one influential paper, explains why extra weight after menopause can be protective for bone health, and explores emerging connections between vitamin D, sleep regularity, and the gut microbiome in healthy aging.

Professor Roy Taylor returns three years after his first appearance to discuss the definitive five-year results from the DiRECT trial. The evidence confirms that type 2 diabetes is driven by excess fat in the liver and pancreas, and that substantial weight loss can produce durable remission—but only if the weight stays off. Taylor also breaks down what GLP-1 receptor agonists can really do, where the marketing runs ahead of the science, and why concerns about muscle loss require perspective rather than panic.

Can you meaningfully improve type 2 diabetes without losing weight? Dr Nicola Guess, a registered dietitian and Senior Research Fellow at the University of Oxford, presents evidence that a higher-protein, lower-carbohydrate diet can lower post-meal glucose more than medication, without weight loss. The discussion covers why glucose only causes direct harm at diabetic levels, how protein wakes up “sleepy” beta cells, and what overfeeding trials reveal about insulin and obesity. They also address fruit fear, insulin-first theories of obesity, GLP-1s and muscle loss, and metabolic health during menopause, PCOS, and shift work. This episode is a clear-eyed guide to metabolic health without the hype.

In this episode, host Simon Hill speaks with urologist Dr Michael Eisenberg and reproductive endocrinologist Dr Natalie Crawford about male fertility, often overlooked despite contributing to half of infertility cases. They explain that ejaculating normally does not guarantee fertility, and a semen analysis is the critical first step. The conversation reveals that sperm health may be a powerful window into overall wellness, with one Danish study linking semen quality to lifespan. They also discuss testosterone therapy as a temporary contraceptive, the alarming global decline in sperm counts driven by endocrine disruptors and lifestyle, and how sperm can regenerate within three months, making it a rapidly improvable health metric.

Dr. Terry Simpson returns to The Proof for a wide-ranging conversation on heart disease prevention and healthy ageing. He explains why lifestyle choices matter more than genetics for maintaining a sharp brain as we age, and unpacks how PCSK9 inhibitors work by framing plaque buildup as a geological process. The discussion also covers gene editing for cholesterol, functional cures for type 1 diabetes, the lean mass hyperresponder debate, and new 2026 guidelines that recommend testing Lp(a) once. Along the way, Simpson and host Simon Hill air frustrations about misinformation outrunning careful science.

Simon Hill compiles insights from leading researchers to explore the science of metabolic flexibility and what can be done to improve it. The conversation centers on mitochondrial function, with lactate serving as a diagnostic window, the reality of energy balance demonstrated in controlled chamber studies, and the groundbreaking understanding that type 2 diabetes can be reversed through significant weight loss. The episode explains the twin cycle hypothesis and the concept of a personal fat threshold, shedding light on why some people are more susceptible to metabolic disease. It also examines the roles of dietary sugar and saturated fat in liver fat accumulation and establishes Zone 2 training as a powerful tool for metabolic health.

A masterclass on GLP-1 medications and weight loss featuring insights from five experts. It covers how these drugs reduce 'food noise' and appetite, why obesity is a chronic disease not just about willpower, the surprising origin of GLP-1 drugs in Gila monster venom, the importance of nutrition and resistance training during treatment, the benefits of a Mediterranean-style diet for long-term weight maintenance, and the stigma and shame often associated with using medication for weight loss.

This episode challenges the assumption that a child's health journey begins at birth. Dr Federica Amati, Head Nutritionist at ZOE, explains how the months before conception and the first 1,000 days shape fertility and lifelong health. She discusses the 90-day preconception window for both parents, the surprising role of a father's metabolic health in brain development, and what the dramatic decline in sperm counts means for individuals. The conversation balances striking science with a compassionate, guilt-free approach, emphasising the policy and environmental factors that often outweigh individual choices.

Host Simon discovers through repeated CT scans that his arterial plaque volume dropped 40% over 16 months. Dr. Campbell Rogers, an interventional cardiologist and CMO at Heartflow, explains the difference between calcium scores and soft plaque detection, why seeing your plaque matters for medication adherence, and the honest limitations of plaque imaging technology. The conversation bridges the gap between what we can now visualize and what we still don't fully understand about heart disease progression.

Simon Hill, host of The Proof, ranks eight popular heart supplements by the strength of the human evidence for reversing arterial plaque. After a 2024 scan revealed early plaque in his own left anterior descending artery, he examined the data behind EPA, standard fish oil, aged garlic extract, vitamin K2, niacin, CoQ10, berberine, nattokinase, and pomegranate extract. Only pure prescription EPA had strong, replicated trial data showing actual plaque regression and reduced cardiac events, while niacin became a classic biomarker trap and the others lacked high‑quality proof. The episode mixes a rigorous look at the trials with his personal decision to focus on the proven basics.

Dr Mauricio Gonzalez challenges the conventional weight-centric approach to metabolic health, arguing that liver fat is a more critical metric. He discusses the minimum effective dose of exercise, the transformative role of GLP-1 drugs in diabetes clinics, and why continuity of care reduces mortality. The conversation also covers patient guilt around taking medication, how nutrition advice has evolved, and which supplements are worth considering alongside GLP-1s.

Exercise physiologist Dr. Margie Davenport, who chaired the 2019 Canadian Physical Activity Guidelines for Pregnancy and the 2025 postpartum guideline, dismantles historical prohibitions on exercise during pregnancy with evidence. The episode covers the origin of outdated rules (like the 140 bpm limit), concrete benefits (40% fewer cases of preeclampsia and gestational diabetes, 67% fewer cases of depression), what fetal monitoring actually shows during HIIT and heavy lifting, postpartum recovery data, and a paradigm shift from blanket restrictions to shared decision-making with pregnant athletes.

Dr Federica Amati, Head Nutritionist at ZOE and author of The Appetite Reset, discusses the biology of appetite and satiety, including the three types of hunger and how GLP-1 medications work. She explains why natural GLP-1 lasts only minutes while drug versions last days, why over-the-counter supplements can't replicate the effects, and the importance of prehabilitation—gut microbiome diversity, fibre, and nutrient status—before starting medication. She emphasizes protein intake of 1.2–1.6 g/kg and resistance training three times a week to protect muscle and bone during weight loss, and unpacks the science on weight stigma as a barrier to effective treatment.

In this episode, bariatric surgeon and science communicator Dr. Terry Simpson joins Simon Hill to tackle health misinformation, GLP-1 drugs, statin controversy, and the legacy of Ancel Keys. Simpson shares his personal journey with familial hypercholesterolemia and a 50-pound weight loss on tirzepatide. The conversation covers how to spot health hucksters, the science behind GLP-1s derived from Gila monster venom, the silencing of food noise by the medication, and a robust defense of statin therapy using ApoB as a superior risk marker. Simpson also defends the Mediterranean diet based on a trial that was stopped early for ethical reasons, and warns against the dangers of unregulated compounded GLP-1s. The episode blends clinical expertise with first-hand experience in the culture wars of nutrition science.

Sarah Ann Macklin challenges the assumption that more optimization equals better health. Drawing on research and her own experience collapsing under wellness culture pressure, she explores how perfectionism in health habits creates anxiety rather than wellbeing, and why self-compassion—not discipline—is the actual foundation of sustainable behavior change.

Bruce Friedrich, founder of the Good Food Institute and author of Meat: How the Next Agricultural Revolution Will Transform Humanity's Favorite Food and Our Future, returns to discuss why public health messaging on meat has failed for 60+ years and why the solution isn't asking people to eat less but rebuilding meat itself from the ground up. The conversation covers the four harms of industrial animal agriculture, the collapse of Beyond Meat, where cultivated meat actually stands in 2026, why this transition requires government support beyond venture capital, and what the science really says about ultra-processed foods.

Simon Hill brings together leading voices in nutrition and cardiology to tackle cholesterol, blood pressure, and heart disease prevention. The masterclass features Harvard's Dr. Walter Willett on saturated fat, seed oils, and dairy; cardiology dietitian Michelle Routhenstein on ApoB testing and food swaps; and nephrologist Dr. Raymond Townsend on sodium and blood pressure. The episode reviews landmark trials, the Portfolio Diet, and the power of combining diet, exercise, and medications.

Dr. Valter Longo, Professor of Gerontology at USC and creator of the Fasting-Mimicking Diet, joins Simon Hill on The Proof to discuss the current hype around peptides and GLP-1 agonists. He argues that growth-hormone-releasing peptides likely accelerate aging, not extend life, and reveals the body composition data showing that GLP-1 users lose substantial lean mass and fat, with a 92% dropout rate after 3-4 years. Longo presents evidence from over 47 clinical trials of the Fasting-Mimicking Diet, including biological age improvements, and clarifies the Harvard protein intake data linking animal protein to higher mortality. He also makes a case against ketogenic diets for longevity and shares the optimal IGF-1 range and how to achieve it through diet and meal timing.

Dr Andrea Glenn, a nutrition epidemiologist from NYU and Harvard, joins Simon Hill to examine the strongest evidence on plant-based nutrition. She unpacks new data on the plant-to-animal protein ratio and heart disease risk, explains how the Portfolio Diet can lower LDL as effectively as a statin, and debunks butter and tallow trends with recent mortality data. The conversation also defends the value of nutritional epidemiology and offers a practical roadmap based on the 2026 American Heart Association guidelines.

Registered nutritionist Rhiannon Lambert breaks down the science behind ultra-processed foods, food labeling accuracy, and practical strategies for home cooking. The episode cuts through marketing hype to explain what the evidence actually shows about UPFs and health, the limitations of current classification systems, and how to read nutrition labels without falling into purism.

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.

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.

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.

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.