Peter Attia Revisits Fasting, Keto, Metformin, Rapamycin and Heavy Lifting After 400 Episodes

Longevity advice changes quickly, and the people giving it are expected to change with it. In this Ask Me Anything episode, Peter Attia marks 400 episodes of The Drive by revisiting positions he has taken over eight years. He frames the exercise as strong convictions, loosely held: updating beliefs as new evidence, expert conversations, and clinical experience arrive is, in his view, essential to practicing medicine well.

The discussion spans nutrition, drugs, cancer screening, and exercise. On nutrition, Attia describes how his views on ketogenic diets, energy balance, and dietary dogmatism have evolved. He covers extended fasting, including autophagy, lean-mass loss, and who might benefit from prolonged fasts. He also discusses the dietary restriction, time restriction, and calorie restriction framework, and why GLP-1 agonists are tipping the balance toward calorie restriction.

On drugs, he explains that he no longer views metformin as geroprotective for metabolically healthy people and has stopped taking it for longevity. He describes growing uncertainty about rapamycin: the animal data are compelling, but human dosing remains unresolved.

On cancer screening, he stresses the importance of early detection but notes declining whole-body MRI quality and points toward more targeted alternatives. He calls liquid-biopsy technology, including the NHS-Galleri trial, still fuzzy, and argues that detecting early-stage rather than late-stage cancer is what matters.

On exercise, he discusses the limits of the 80/20 Zone 2 framework, how to program cardio at lower training volumes, and how to build a training habit without forcing workouts. He has moved away from heavy barbell squats and deadlifts, favoring alternative exercises and deliberate management of injury risk.

The overarching message is to prioritize principles, foundations, and sustainable practices over marginal optimization. Caveat: this is one clinician's opinion and not a systematic evidence review, and this summary draws only on the episode description.