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Why Does Eating Less Increase Life Span?
17 Apr 2014
Nematode worms, fruit flies, mice and other lab animals live longer, healthier lives when they eat less than they otherwise would if more food were available. Primates may also benefit, and perhaps humans — which is why research funds are pouring into this phenomenon. But all this raises a puzzling question: Why did creatures evolve such a mechanism in the first place? Researchers have declared the most popular theory doesn’t make evolutionary sense, and they’ve proposed a new explanation in its place.
 
The most prominent theory involves what happens physiologically during times of food scarcity. When the living is good, natural selection favors organisms that invest energy in reproduction. In times of hardship, however, animals have fewer offspring, diverting precious nutrients to cell repair and recycling so they can survive until the famine ends, when reproduction begins anew. Cell repair and recycling appear to be substantial antiaging and anticancer processes, which may explain why underfed lab animals live longer and rarely develop old-age pathologies like cancer and heart disease.