What is calorie restriction?
Calorie restriction means eating noticeably fewer calories than usual, often 10 to 30 percent less, while still getting all the nutrients you need.
Think of an engine that's always run at full throttle versus one that's run a bit gentler. The gentler engine produces less wear and tends to last longer.
Why it matters for aging
Calorie restriction is the most consistent way to extend lifespan in lab animals, from yeast and worms to mice. In monkeys, it improved health markers. The likely reason is that less incoming food turns down growth signals like mTOR and IGF-1 and turns up repair processes like autophagy.
In humans, the CALERIE trial tested it in healthy adults for two years. Results were modest but real. The catch is that strict calorie restriction is hard to sustain, and going too far can cause muscle loss, low energy and weaker bones, especially in older adults.
A common myth
Calorie restriction means starving yourself.
It means eating somewhat less while staying well nourished. In a two-year human trial, people who cut calories by about 12 percent slowed one measure of their pace of aging by 2 to 3 percent.
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Updated Nov 9, 2026 · All terms