What it is
Caloric restriction (CR) means eating fewer calories than usual while still getting adequate nutrition. It is the most studied dietary intervention in ageing research and a reference point for fasting and CR-mimetic drugs.
Why it matters for longevity
CR reliably extends lifespan and healthspan in species from yeast to rodents, acting on nutrient-sensing pathways such as mTOR and boosting autophagy. This is the biology many longevity diets and drugs try to imitate.
What the evidence shows
In humans, the two-year CALERIE randomised trial showed CR is feasible in healthy adults and improves cardiometabolic risk markers and even a measure of pace-of-ageing. But it was not designed to test lifespan, primate studies have given mixed results, and aggressive restriction carries risks (muscle and bone loss, disordered eating).
Bottom line
Moderate CR has credible metabolic benefits; framing it as a proven life-extender in humans overstates the evidence.