A single hormone appears to coordinate the lifespan extension produced by a low-protein diet. Low-protein diets produce beneficial metabolic effects in aged mice, improving metabolic health, reducing frailty, and extending lifespan. These beneficial effects were also apparent when protein intake was reduced in middle-aged mice, even protecting against the detriments of obesity. Importantly, these beneficial effects were lost in mice that lacked FGF21, suggesting that its action in the brain is critical for the increase in health and lifespan. https://www.sciencedaily.com/releases/2022/05/220513103509.htm
