A diet has been named that allows you to eat more while still losing fat

A low-protein diet supplemented with an optimal amount of the amino acid methionine following Mediterranean principles reduces fat mass, improves metabolism, and decreases signs of aging — all without calorie restriction. The study by scientists from the University of Southern California in collaboration with colleagues from the University of Toronto and Harvard has been published in the journal Cell Metabolism.

First author Mauro Fanti and Professor Valter Longo tested the so-called LDMM diet on aged mice at 20 months old. The animals ate more food than the control group, yet lost fat mass and showed fewer signs of aging. Levels of the hormones GLP-1 and FGF21, associated with metabolism and longevity, were elevated in these mice.

Methionine is an essential amino acid found abundantly in meat, fish, and eggs. Too little methionine in the diet triggered weakness and bone fragility; too much completely negated the protective effect of the diet. What proved crucial was not the overall amount of protein, but its amino acid composition.

"Amino acid composition, not simply protein quantity, determines the body's metabolic response," explained Mauro Fanti.

"Too little methionine — fragility, too much — and all the benefits disappear," added Valter Longo.

In parallel, the authors analyzed data from more than 200,000 people: lower consumption of animal protein correlated with half the rate of obesity and type 2 diabetes. A fully plant-based diet also carries risks when methionine is insufficient — precise balancing of protein sources is what matters, not simply eliminating meat products.