Valter Longo's low‑protein longevity diet extends healthy lifespan in mice

An international research team led by Italian scientist Valter Longo, based at the University of Southern California, introduced a low‑protein, plant‑based diet supplemented with small amounts of methionine—called the “longevity diet.” In mouse experiments, the regimen boosted health‑span, reduced body fat and fragility, and allowed the animals to eat more than other groups.

The study, published in Cell Metabolism, also incorporated analysis of data from over 200,000 people, drawing on collaborations with the University of Toronto and Harvard University. Researchers found that human health outcomes mirrored the animal results, showing lower rates of obesity and type‑2 diabetes when following a diet rich in vegetables, fish and limited protein.

“Modulating a single amino acid, methionine, produced dramatic metabolic changes,” noted lead author Maura Fanti, emphasizing that amino‑acid composition, not just total protein, may be a strategic target for metabolic interventions.