Review Links Excess Protein to Shorter Lifespan in Inactive Adults
A review of over 350 studies suggests that high protein intake may reduce longevity in sedentary people, especially when the protein comes from certain sources, and recommends personalized diets and more activity.
Researchers at the University of Wisconsin-Madison examined more than 350 studies and found that while protein supports muscle growth, intake beyond the body's needs offers little benefit and may shorten lifespan in inactive adults, particularly when derived from specific amino-acid profiles.
The analysis highlights that optimal protein levels vary with age, activity level and overall health. For people who are largely sedentary, reducing excess protein and increasing physical activity can improve how nutrients are utilized.
"We are hearing conflicting things from doctors ... and influencers," said Tanya Freirich, a registered dietitian nutritionist in Charlotte, North Carolina. "The message lately has been to increase your protein, but excess protein is associated with negative effects, such as strain on kidney health and interference with bone and calcium homeostasis."
Freirich added that active individuals, especially those engaging in strength training or sports, may require slightly more protein, whereas those whose activity levels drop should adjust their intake accordingly.
She recommended a balanced plate of roughly 50% vegetables, 25% protein and 25% whole grains, a protein target of about 0.8 g per kilogram of body weight for low-activity adults and 1.0 g per kilogram for more active people, and a shift toward plant-based protein sources such as lentils, beans and seeds. Whole, minimally processed foods were also advised to support natural satiety and overall regulation.
Overall, the review urges individuals to consider personal circumstances and consult healthcare providers rather than relying on single headlines or trends.