Do you consume protein for good health? Scientists say eating less could slow ageing & improve your metabolism

Protein-rich cereals, coffee, snack bars and even protein-infused water have become increasingly popular as more people look to boost their daily protein intake. However, a new scientific review, as cited by News Medical, suggests that, for many adults, consuming less protein could actually offer greater health benefits and may even support healthy ageing.

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The review, published on July 31 in the journal Cell Press Blue, analysed more than 350 studies on protein restriction and ageing. Researchers concluded that reducing protein intake may improve metabolism, lower inflammation, protect healthy cells and, in some cases, extend lifespan. The findings also suggest that eating less protein could help improve blood sugar control and reduce the risk of certain age-related diseases.

New research explores how protein affects ageing

The review was led by researchers at the University of Wisconsin-Madison, who examined decades of evidence on protein restriction in animals and humans. According to the researchers, limiting protein intake appears to slow biological ageing by changing how cells respond to nutrients, reducing cellular damage and preserving normal cell function.

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Dudley Lamming, the paper's corresponding author from the University of Wisconsin-Madison, said the benefits of protein depend on an individual's lifestyle.

"It's absolutely crystal clear that there are benefits of protein to muscle growth and exercise response of active individuals. But because most people are relatively sedentary, many people are likely consuming more protein than they actually need, which probably has negative health consequences," Lamming was quoted as saying by News Medical.

Why eating less protein may benefit metabolism and blood sugar

According to the review, one of the main biological mechanisms involves a hormone called fibroblast growth factor 21 (FGF21), which increases when protein intake is reduced.

Researchers found that higher FGF21 levels can increase energy expenditure, improve blood sugar regulation and reduce inflammation. Animal studies have also linked elevated FGF21 levels with a longer lifespan, particularly in male mice. Previous human studies have similarly shown that reducing protein intake raises FGF21 levels.

The review also highlights that consuming lower amounts of certain amino acids, including methionine, isoleucine and valine, may contribute to healthier metabolism by reducing biological processes linked to obesity and age-related diseases.

Previous studies found similar health benefits

The authors noted that scientists have long known that calorie restriction can extend lifespan in several organisms and lower the risk of diseases such as cancer. However, maintaining a low-calorie diet is often difficult.

Earlier studies have shown that protein restriction can extend the lifespan of flies and rodents without reducing calorie intake. Several clinical trials in humans have also found that reducing dietary protein may lower body weight, decrease fat mass and improve fasting blood sugar levels, even when participants consumed more calories overall.

More protein is still important for some people

The researchers also acknowledged that higher protein intake remains beneficial for certain groups.

Previous studies have found that consuming more protein, especially alongside regular exercise, can help older adults preserve muscle mass and support weight loss. Those findings contributed to updated US dietary guidelines recommending daily protein intake of 1.2 to 1.6 grams per kilogram of body weight for many adults.

Lamming suggested that physically active people may process protein differently because exercise helps the body use it to build and maintain healthy muscle.

"Recent recommendations have encouraged people to eat more protein, but they've also encouraged people to exercise more," he told News Medical. "We probably need to personalise protein recommendations based not just on age, but also on how physically active people are."

Researchers say protein needs should be personalised

Despite the growing popularity of protein-fortified foods, the researchers believe they may not provide the expected health benefits for everyone.

According to Lamming, while pregnant women, athletes and some older adults have higher protein requirements, many sedentary adults may already be consuming more protein than their bodies need.

The researchers concluded that future dietary advice should take into account not only age but also physical activity levels, as the ideal amount of protein may differ significantly from person to person.


Disclaimer: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.