Eating less protein, rather than cutting calories, may be a more manageable route to a longer and healthier life for sedentary adults, according to a new scientific review.

The review points to a dietary shift that differs from decades of attention on calorie restriction. Previous research has long linked eating fewer calories with improved lifespan and lower rates of disease linked to aging, but strict low calorie diets can be difficult for many people to maintain.

A review of more than 350 studies published in the journal Cell Press Blue suggests that targeted protein restriction may offer similar metabolic benefits without requiring people to reduce calories.

Across the studies included in the review, lower protein intake was associated with better metabolism, changes in nutrient signaling, reduced cellular damage and improved cellular maintenance, according to the published paper.

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The findings focus especially on sedentary adults. While research has shown that higher protein intake can benefit active people, the review suggests the opposite may be true for people who do not exercise regularly.

Much of the reported benefit is connected to a metabolic hormone called fibroblast growth factor 21, or FGF21. Restricting protein triggers a surge in FGF21, which animal studies have shown can boost energy expenditure, reduce inflammation, improve blood sugar control and extend lifespan.

The researchers also highlighted three essential amino acids that are building blocks of protein. Those amino acids are methionine, isoleucine and valine.

Under certain conditions, the review says those amino acids may contribute to biological pathways associated with aging. For people who do not exercise regularly, high levels of those amino acids may keep certain growth related processes active.

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Over time, that stimulation can create cellular damage, systemic inflammation and weight gain, according to the review. The researchers said that because many people are relatively sedentary, many may be consuming more protein than they actually need.

Dudley Lamming, the paper’s corresponding author, emphasized that protein still has clear benefits for people who are physically active. The review does not frame protein as harmful for everyone.

Instead, it draws a sharp distinction between active and sedentary people. Physically active people and athletes process protein differently, because exercise helps direct dietary amino acids toward building and repairing muscle.

For those groups, dietary amino acids associated with protein intake are crucial for building muscle tissue. High protein intake is also crucial for pregnant women and older adults who may face muscle loss linked to age.

The review also notes important limits to the findings. Because the paper is a scientific review rather than a new clinical trial, it can identify patterns across existing research but cannot prove cause and effect in humans.

Longer term human studies are still needed to determine whether the metabolic benefits described in the review ultimately translate into increased lifespan. The researchers acknowledged that the evidence does not yet establish that outcome in people.

The review also stresses that protein needs are not the same for everyone. Its findings should not be interpreted as a recommendation to consume inadequate amounts of protein.

For the broader population that is largely inactive, the findings suggest that public health guidelines should become more personalized. Rather than relying on sweeping protein recommendations, the review points toward targets based on a person’s age and activity level.

The central message is therefore cautious rather than extreme. Eating less protein may offer metabolic benefits for sedentary adults, but the review also makes clear that activity level, pregnancy, age and muscle needs all matter when considering protein intake.