quixote9 writes "Calorie restriction while maintaining nutrient levels has long been known to dramatically increase life spans. Very different lab animals, from worms to mice, live up to 50% longer (or even more) on the restricted diets. However, so far, nobody has been able to figure out how this works. Scientists at the Salk Institute have found a specific gene in worms (there's a very similar one in people) that is directly involved in the longevity effect. That opens up the interesting possibility that doctors may someday be able to activate that gene directly and we can live long and prosper . . . without giving up chocolate."