A new study suggests that moderate calorie reduction may slow down aging processes—without harming overall health. The findings were published in the journal Nature Aging.

Previous experiments in animals—from mice to primates—have already shown that calorie restriction can increase lifespan and reduce the risk of disease. However, excessive dietary restriction can lead to serious side effects, including weakened immunity, reduced reproductive function, and slowed growth.

In the new study, researchers focused on a more moderate approach. In a long-term clinical trial, participants reduced their daily calorie intake by about 11–14% over two years—without experiencing significant hunger or nutrient deficiencies.

The results showed that this moderate diet had a positive effect on the immune system. In particular, researchers observed a decrease in levels of the C3 protein—a component of the immune system associated with chronic inflammation. Chronic inflammation is considered one of the key drivers of aging and age-related diseases.

A reduction in the activity of this protein may indicate that the body shifts into a healthier functional state, lowering inflammation without compromising its ability to fight infections. Thus, the effect goes beyond simple weight loss and reflects deeper biological changes influencing the mechanisms of aging.

Scientists emphasize that the findings support an important idea: aging is not an entirely fixed and inevitable process, but one that can be influenced. However, they also stress that moderation is key. Severe calorie restriction can be harmful, whereas a mild reduction appears to be both beneficial and safe.