It's not just how much protein you eat — it's what kind. A new USC study found that a modified Mediterranean diet low in the amino acid methionine helped mice lose fat, reduce frailty, and live healthier longer. An analysis of 200,000+ people backed it up, linking lower animal protein intake to reduced obesity and Type 2 diabetes rates.
Forget calorie counting — a new study from USC suggests the type of protein you eat may matter more than the amount. Researchers found that a modified Mediterranean-style diet, low in the amino acid methionine (found in eggs, meat, and dairy) but supplemented with just enough of it, helped aging mice lose body fat, reduce frailty, and extend their healthspan. The findings were published in Cell Metabolism.
What made the results especially striking: mice on this "longevity diet with modified methionine" (LDMM) actually ate more food than the other groups — yet still shed fat while preserving lean muscle. The diet also boosted GLP-1 and other metabolic signaling molecules linked to healthy aging.
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Why it matters: These findings challenge the long-held belief that weight loss requires calorie restriction, pointing instead to amino acid composition as a key metabolic lever. Researchers plan to test the LDMM in human clinical trials next.
