Nutrition Science

Eating Less Protein Could Slow Aging, Major Review of 350+ Studies Finds

A sweeping review of more than 350 studies suggests that consuming less protein — not more — may improve metabolism, reduce inflammation, and activate longevity pathways.

For years, the message has been clear: eat more protein. Protein bars, protein shakes, high-protein diets — the booming industry has convinced millions that more protein means better health. But a sweeping new review of more than 350 scientific studies, published in the journal Cell Press Blue, suggests that the protein boom may be overselling what many people actually need.

Researchers from the University of São Paulo and the Albert Einstein College of Medicine analyzed decades of research on protein restriction and aging. Their conclusion: eating less protein — or fewer of the specific amino acids that make up protein — appears to improve metabolism, reduce inflammation and cellular damage, and activate pathways linked to longer, healthier lives.

The review examined studies across species, from yeast and worms to rodents and humans. In nearly every model tested, reducing protein intake triggered a set of cellular defense mechanisms that slowed aging. The key pathways involved — mTOR, FGF21, and autophagy — are the same systems targeted by popular longevity drugs and intermittent fasting regimens.

"The evidence is remarkably consistent," the authors wrote. "Protein restriction reliably improves metabolic health and extends lifespan in diverse organisms."

One of the most striking findings involved the amino acid methionine, which is abundant in meat, eggs, and dairy. Reducing methionine intake alone, even without cutting total calories, produced many of the same benefits as full protein restriction — including lower oxidative stress, better insulin sensitivity, and reduced inflammation.

In human studies, participants who consumed protein at the lower end of the recommended range (around 0.8 grams per kilogram of body weight per day) showed improved markers of metabolic health compared to those eating high-protein diets. The benefits were especially pronounced in middle-aged and older adults, who may be consuming far more protein than their bodies can effectively use.

The review does not suggest that protein is harmful. Rather, it challenges the assumption that more is always better. For adults who already meet basic protein requirements, pushing intake higher — especially through supplements — may do more harm than good, particularly when it displaces other nutrient-rich foods.

For those interested in healthy aging, the researchers recommend focusing on whole foods, balancing protein intake with vegetables and fiber, and avoiding the "more is better" mindset that drives the protein supplement industry.