#411 ‒ AMA #90: Strong convictions, loosely held: how Peter's views on fasting, keto, metformin, rapamycin, whole-body MRI, and exercise have changed

Peter Attia reviews how his clinical positions have shifted after 400 episodes of The Drive. He explains why changing his mind in response to new evidence is central to good medicine. He revisits nutrition, detailing how his views on ketogenic diets and extended fasting have evolved. He describes why he stopped taking metformin for longevity, shares growing uncertainty about rapamycin dosing in humans, and critiques the declining quality of whole‑body MRI combined with the still‑fuzzy results of liquid biopsies. On exercise, he acknowledges limitations of the 80/20 Zone 2 framework for time‑constrained people and describes a move away from heavy squats and deadlifts in favor of risk‑managed alternatives. Throughout, he emphasises focusing on durable principles and sustainable practices over marginal optimisations.