Strong convictions, loosely held: how Peter’s views on fasting, keto, exercise, & more have changed

What happened in this episode?

In a short “Strong convictions, loosely held” reflection episode marking roughly 400 episodes of The Drive, Peter Attia explains how he updates his views in response to new information from the scientific literature, expert interviews and clinical experience. He revisits his earlier enthusiasm for carbohydrate restriction and ketogenic diets, saying he followed a strict ketogenic diet for about three years and “felt” better than at any other time, but ultimately stopped because of the burden of dietary restriction rather than because he considers keto ineffective.

Attia’s central update is conceptual: he says he no longer believes ketogenic diets primarily work through insulin suppression. Instead, he argues their benefits are more plausibly explained by improved control of energy intake and satiety, while maintaining that energy imbalance is the driver of visceral and ectopic fat accumulation and worsening insulin sensitivity, with hyperinsulinaemia a downstream feature rather than the root cause. He also says he is now less prescriptive about whether patients use keto, low-fat or other eating patterns, so long as key principles—especially adequate protein intake—are met.

On fasting, Attia describes a past routine of prolonged fasts (7–10 days quarterly, plus three-day fasts in other months) pursued to stimulate autophagy. He cautions that autophagy is hard to quantify in humans and notes uncertainty about the threshold duration needed for “high autophagy”, offering a tentative view that around three days may be meaningful based on older reading and expert conversations. The episode then transitions into a paywalled promotion for premium membership and AMA content.

What are the key points?

• Attia defines “strong convictions, loosely held” as committing to a thesis while being ready to change with contradictory evidence.
• He says podcasts with domain experts and clinical experience are major drivers of his changing views, alongside literature.
• Attia says he no longer thinks ketogenic diets work mainly via insulin suppression, but via easier energy-intake control and satiety.
• He argues metabolic dysfunction is driven by energy imbalance, with hyperinsulinaemia “along for the ride”.
• He says he is less dogmatic about diet type if protein targets are met, citing a minimum of 1.4 g/kg body weight.
• Attia recounts doing 7–10 day fasts quarterly for about three years, plus three-day fasts in other months, to pursue autophagy benefits.
• He says evidence is unclear on how long fasting must last to substantially increase autophagy in humans, and notes he has not reviewed the literature recently.

Who is speaking?

Named speakers identified in Egleze's source-linked moments from this episode.

• Peter Attia

Which topics are covered?

How is this page sourced?

Programme

Peter Attia Drive

Published

12 October 2026

Duration

17m

Original episode

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