Nutrition experts warn against protein restriction for older adults

A recent review in a Cell Press Blue journal argued that limiting dietary protein could improve metabolic health and increase lifespan. The authors, based at the University of Wisconsin-Madison, compiled data from 350 prior studies, many involving animals, to propose protein restriction as a "geroprotective" strategy.

Nutrition specialists cautioned that the conclusions are not supported for humans, especially older adults. Stuart Phillips, a kinesiology professor at McMaster University, called the paper "a beautiful mouse story, sold as human advice" and noted that low protein intake in people over 65 is linked to higher frailty, more falls and increased mortality.

Experts highlighted that the review did not define the amount of protein reduction needed for sedentary people, and that current U.S. guidelines recommend 0.8 g/kg body weight as the RDA, with the Dietary Guidelines for Americans suggesting 1.2-1.6 g/kg. Donald Layman, who helped set those guidelines, said most Americans already meet the higher range.

William Evans, a protein-aging researcher at UC Berkeley, warned that reducing protein could accelerate muscle loss, particularly for those on GLP-1 weight-loss drugs that already promote muscle catabolism. Registered dietitian Stacy Pelekhaty added that cutting protein without lowering calories may lead to higher carbohydrate intake and greater metabolic risk.

The PROT-AGE study, cited by dietitian Katie Dodd, recommends 1-1.2 g/kg for older adults, with higher amounts for active individuals. Dodd emphasized that healthy aging focuses on maintaining strength and independence rather than merely extending years.

Overall, the consensus among the consulted experts is that protein needs should be individualized, taking age, health status, activity level and kidney function into account, and that functional health should take precedence over unproven longevity benefits.