Cutting calories by 30% may slow brain aging, monkey study reveals

A decades-long study has revealed that cutting calories by nearly a third could slow brain ageing in rhesus monkeys. Researchers tracked the animals from the 1980s until their natural deaths, observing clear benefits in brain health. The findings suggest similar effects might apply to humans—but without the need for extreme dieting.

The research began in the 1980s with 24 male and female monkeys aged 22 to 37. For 20 years, half consumed 30% fewer calories than the control group. Originally, the study aimed to see if the diet would extend their lifespans—and it did.

Post-mortem examinations later showed the calorie-restricted monkeys had less metabolic dysfunction and oxidative damage in their brains. Their glial cells and neuronal connections also remained stronger. These results, published in *Aging Cell*, indicate that long-term calorie reduction may protect brain structure. In humans, combining a modest 10–20% calorie cut with nutrient-rich foods and exercise has already shown benefits. Previous studies link this approach to better insulin sensitivity, lower inflammation, and improved blood pressure. The ongoing CALERIE study continues to explore how calorie restriction affects human ageing biomarkers. Scientists from Boston University and the National Institute on Aging led the monkey research. They stress that extreme restriction isn't necessary for humans. Instead, sustainable, moderate changes could help maintain brain function as people age.

The study provides strong evidence that long-term calorie reduction supports brain health in primates. For humans, a balanced approach—slightly fewer calories, better nutrition, and regular activity—may offer similar protection. Further research will clarify how these findings translate into real-world ageing benefits.