Research

Hormonal

Protein restriction (specifically low-protein, high-carbohydrate diets) extends lifespan and improves metabolic health in model organisms, likely through mechanisms distinct from or overlapping with calorie restriction, such as elevated FGF21.

In model organisms, restricting protein (while keeping calories normal) extends lifespan and improves metabolic health, partly by boosting FGF21. However, this comes at the cost of muscle mass. For humans, high protein is generally recommended for muscle maintenance, but excessive intake might increase mortality risk. The optimal protein intake likely balances longevity benefits with the need to preserve physical resilience, suggesting a moderate approach rather than extreme restriction or excess.

GoodSupportsHIGH confidence
Protein restriction represents an alternate nutritional intervention that improves longevity and health in model organisms... The beneficial effects of protein restriction on metabolism and longevity may come at a cost to lean mass and physical resilience.
Sora Q. Kim et al. · Annual Review of Nutrition · 2025

Why this rating

Strong evidence in rodents/invertebrates, but human data is observational and mixed.

Source

Protein-Restricted Diets and Their Impact on Metabolic Health and Aging

Sora Q. Kim et al. · Annual Review of Nutrition · 2025

DOI 10.1146/annurev-nutr-121624-114918

narrative_reviewCited 9×
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DOI resolved against Crossref · corpus check 2026-06-10

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