For 20 years, study subjects at the University of Wisconsin have been fed a low-calorie diet, with researchers monitoring their health profiles against those who had a normal food intake.

The scientists have found that a good diet that is low in calories decreased the chances of developing cardiovascular disease, diabetes and other conditions, and are hopeful that the results of the studies will allow for further research into the effects of calorie restriction on reducing the effects of aging.

"There is a major effect of caloric restriction in increasing survival if you look at deaths due to the diseases of aging," says lead author Dr Richard Weindruch.

His colleague, Dr Sterling Johnson says that the now elderly subjects are also able to maintain the size of certain regions in the brain that could benefit those who worry about memory decline and decreased ability to fluidly move around.

"Both motor speed and mental speed slow down with aging," Johnson explained. "Those are the areas which we found to be better preserved."