Many People Eat Too Much Protein, Researcher Warns—Here’s Why It Could Age You

A review of more than 350 scientific studies published Friday found booming protein food options at grocery stores may be harming many Americans who lead sedentary lifestyles and do not need the extra intake.

The review published in Cell Press Blue found reducing protein intake instead of increasing it may slow aging and potentially extend lifespan.

Dudley Lamming, the review's corresponding author at the University of Wisconsin-Madison, said in a statement, “Because most people are relatively sedentary, many people are likely consuming more protein than they actually need, which probably has negative health consequences.”

The review points out a hormone known as fibroblast growth factor 21, which rises when protein intake is reduced, to boost energy, blood sugar control and reduce inflammation.

Amino acids within high-protein diets like ethionine, isoleucine, and valine appear to activate growth pathways that raise risks of obesity, inflammation and other age-related diseases, according to the review.

U.S. dietary guidelines under Secretary of Health Robert F. Kennedy Jr. recommend a daily protein intake of 1.2 to 1.6 grams per kilogram of body weight, nearly double the previous target, according to the review.

Nearly 100 grams. That is how much protein the average American man eats daily, which is roughly twice the previously recommended limit before it was adjusted by the Trump administration.

Human clinical trials have found people who ate less protein lost weight and body fat while improving their fasting blood sugar, even if they consumed more total calories. For Americans who are less sedentary, Lamming notes athletes appear to be protected from the downsides of high protein intake because exercise sends extra amino acids into muscle instead of pathways linked to disease. He added in his statement that protein recommendations should not just be based on age, “but also on how physically active people are.”