🧠 Episode Overview What if aging is shaped not only by what you eat, how much you exercise, or which genes you inherit — but also by when your body does things each day?In this episode of The ReProgram, Dr. George Murphy sits down with Dr. Mimi Shirasu-Hiza at the Gordon Research Conference Systems Aging Meeting in Maine.Dr. Shirasu-Hiza is a Professor of Genetics and Development at Columbia University and an international expert in circadian gene regulation, aging, and health.This conversation explores circadian rhythms as daily, approximately 24-hour oscillations in gene expression, tissue function, and behavior — and why disruption of those rhythms through shift work, jet lag, irregular sleep, or mistimed eating may affect metabolism, cardiovascular risk, obesity, cancer risk, and aging biology.A major focus is time-restricted eating: not simply eating less, but aligning eating and fasting with the body’s active and resting phases. Dr. Shirasu-Hiza discusses work in fruit flies showing that time-restricted eating can extend lifespan and preserve youthful oscillations in genes involved in metabolism, protein translation, immune defense, stress response, and other core biological programs. 🔑 Keywords Circadian rhythms, circadian clock, biological rhythms, time-restricted eating, intermittent fasting, caloric restriction, meal timing, fasting window, overnight fasting, metabolism, cardiovascular disease, obesity, cancer risk, aging biology, longevity science, geroscience, exercise, healthspan, resilience, ReProgram Podcast, Dr. George Murphy 🧠 Takeaways • Circadian rhythms are daily, approximately 24-hour oscillations in gene expression, tissue function, and behavior. • The circadian clock is not just about sleep; it helps coordinate transcription, metabolism, feeding, fasting, activity, tissue function, and recovery. • Circadian disruption is associated with cardiometabolic disease, obesity, and cancer risk, especially in shift workers, frequent travelers, and others whose activity occurs during the usual rest phase. • Time-restricted eating is different from caloric restriction. It focuses on when food is consumed, not necessarily how many calories are consumed. • Aging may involve loss of rhythmic gene expression. Time-restricted eating preserved youthful oscillations in genes linked to metabolism, protein translation, immune defense, defense response, and stress response. • Meal timing may help reset circadian rhythms during jet lag, suggesting that food can act as a timing cue for the body clock. 🎙️ The ReProgram Perspective This episode is a reminder that longevity science is not only about molecules, supplements, or single interventions. It is also about biological organization.Circadian biology reframes aging as a problem of timing. Genes, metabolism, immunity, tissue repair, behavior, feeding, and fasting are not static processes. They are coordinated across the day.Dr. Shirasu-Hiza’s work in flies is powerful because it shows that preserving youthful gene-expression rhythms may be linked to lifespan and health. But the translation to humans requires care. The takeaway is not that everyone should follow one rigid fasting window. The takeaway is that timing is biology — and maintaining rhythm may be one underappreciated part of resilience, recovery, and healthy aging. Chapters 00:00 Can Meal Timing Slow Aging? 02:16 Introduction from the Systems Aging GRC 03:08 What Are Circadian Rhythms? 03:46 Shift Work, Jet Lag, and Health Risk 04:30 Circadian Disruption and Cancer Risk 04:59 Time-Restricted Eating vs Intermittent Fasting 05:29 Eating Windows and Overnight Fasting 06:20 Why Fruit Flies Are Powerful Aging Models 07:17 The “Keep Me Young” Genes 08:47 Fasting, Foraging, and Exercise-Like Behavior 09:37 Can Drugs Mimic Circadian Benefits? 10:37 Meal Timing and Jet Lag 12:03 Calories, Diet Type, and Individual Differences 13:03 Closing Reflections
