A 2-Year Randomized Controlled Trial of Human Caloric Restriction: Feasibility and Effects on Predictors of Health Span and Longevity

Researchers randomly assigned 218 healthy, non-overweight adults aged 20 to 50 to either reduce their calories or keep eating normally for two years. The calorie-reduction group aimed to eat 25% fewer calories but managed about 12% fewer. They lost about 8 kilograms, compared with about 2 kilograms in the comparison group. They also had improvements in blood pressure, cholesterol, blood sugar, and some other measures linked with heart health. The study did not measure whether anyone lived longer.

What this means for you: Eating somewhat less may improve several health measures, but this study does not prove it extends life. It supports modest calorie reduction for suitable adults, not expensive diet products or extreme restriction.