The Proof with Simon Hill

Dr Valter Longo, USC gerontology professor who developed the Fasting‑Mimicking Diet, cuts through the peptide craze. He contrasts short‑term GLP‑1/body‑composition claims with long‑term risks. He explains optimal IGF‑1 ranges, plant‑forward protein timing, and why periodic fasting cycles may rejuvenate biology. He warns against DIY peptide stacking and favors evidence‑based lifestyle approaches.

Dr Andrea Glenn, an NYU assistant professor and nutrition scientist with Harvard ties, breaks down the strongest evidence on plant versus animal protein and dietary patterns. She explores the Portfolio Diet and its LDL-lowering power compared to low-dose statins. They discuss butter versus plant oils, the CHEAP trial design, and why nutrition epidemiology still matters.

Rhiannon Lambert, a registered nutritionist and bestselling author, breaks down food processing, fiber and label tricks in clear, practical terms. She explains limits of NOVA, why calorie labels mislead, and which additives merit concern. Learn quick label checks, simple low-effort cooking hacks, and which ultra-processed items to really watch.

Dr Leigh Baxt, a research scientist (PhD microbiology & immunology) who leads drug development and explains peptide science. She unpacks what peptides are and the gap between FDA-approved medicines and unregulated online products. Short takes cover why lab results often fail to translate, the risks of marketing research-only compounds as treatments, and how to evaluate peptide claims critically.

Dr Belinda Beck, professor and leader in bone densitometry and exercise research. She challenges old advice on bone health. Heavy resistance training, impact and load magnitude get center stage. DEXA limits, menopause effects, combining meds with exercise, and risks of common weight-loss drugs are all discussed.

Dr Tim Spector, professor of genetic epidemiology and ZOE co-founder who leads large-scale microbiome research. He discusses a 34,000-sample microbiome ranking, why diversity alone is misleading, a practical guide to fermented foods, the TMAO link between gut bugs and cardiovascular risk, the estrobolome and menopause–microbiome connections.

Dr Kevin Hall, physiologist and nutrition scientist known for metabolic ward studies on ultra-processed foods and energy balance. He discusses what controlled feeding trials reveal about why ultra-processed diets drive higher calorie intake. Conversation covers energy density, hyper‑palatable foods, reformulation possibilities, individual variability and implications for dietary guidelines and policy.

Dr Lora Giangregorio, a Tier 1 Research Chair in Bone Health and Exercise Science, explains practical ways to train for stronger bones and better balance. She discusses why starting where you are matters. She outlines the three pillars: balance, resistance, and impact training. She covers progressive overload, effort over absolute weight, and safely introducing impact work.

Dr Ty Beal, a global nutrition scientist working on nutrient access and policy. Dr Christopher Gardner, a Stanford nutrition researcher who ran major diet trials and served on the Dietary Guidelines committee. They debate ultra-processed foods, protein needs and aging, plant-based meats versus conventional meat, fortification and equity, and how evidence and messaging shape national dietary advice.

Dr Kristen Knutson, a sleep and circadian researcher who chairs the American Heart Association statement on circadian health. She explores how morning light, meal and exercise timing, and regular sleep schedules shape metabolism and cardiovascular risk. The conversation covers light therapy, melatonin timing, wearables' limits, and practical tips for handling overnight awakenings.