Put down that Ho-Ho if you want to live. Once thought to be a kooky fad, calorie restriction may actually help people live longer and improve quality of life in old age according to the results of a study on rhesus monkeys.

Where creams, ‘miracle elixirs’, vitamin concoctions and other potions aimed at fighting off old age have failed, going on a strict diet with limited calorie intake may be the method that really works. Such a diet includes all of the ingredients needed for optimal health, but cuts calories by 30 percent.

The results of a decades-long study on monkeys were reported Thursday in Science by researchers Ricki J. Colman and Richard Weindruch of the University of Wisconsin, illustrating that monkeys given a reduced-calorie diet are showing a number of beneficial signs including less diabetes, cancer, heart and brain disease.

“It says much of the biology of caloric restriction is translatable into primates,” says Weindruch, “which makes it more likely it would apply to humans.”

While these results are encouraging, not everyone is convinced that it will apply to humans, and a 30 percent reduction in calories can be very difficult to maintain. Biologists have begun the search for drugs that might mimic the effect of reducing calories, with one possibility being reservatrol, a substance found in red wine.

Weindruch and his colleagues plan to continue monitoring the monkeys, whose life spans range from 27 to 40 years. The monkeys in the test group are currently in their mid- to late-20s.

"If we reach the 40-year-old life span, the study could continue for another 15 years," Weindruch said. "That would probably round out my career."