Methionine tuning for health without frailty

Dietary protein quality, not merely quantity, shapes metabolic health and aging trajectories. Fanti et al. show that moderate methionine supplementation to a low-protein, Mediterranean-inspired diet activates a GH-GLP-1-FGF21 axis that reduces adiposity and frailty without caloric restriction; their findings provide a mechanism for why traditional plant-rich diets may promote longevity while sometimes compromising physical robustness.