We already know that many of the beneficial effects of calorie restriction observed in short-lived mammals (such as mice) also show up in humans - which is good enough for most practitioners, who expect to see gains in life span carry across as well. Primate studies have been ongoing, and ABC News reports on one set of results: "Hansen has long studied the effects of calorie restriction in roughly 300 rhesus monkeys. Cutting calories can pay off when it comes to longevity: Monkeys fed 30 percent less over the long term extended their lifetimes to 30 years from an average of 23 years, Hansen said. The slimmer monkeys staved off the diabetes, high cholesterol, hypertension and other weight-related ailments that typically shortened the lives of their heavier peers." In fact, it's not clear that healthy life extension due to calorie restriction can be completely ascribed to less fat and lower weight - a lot more is going on under the hood.

Link: http://abcnews.go.com/Health/wireStory?id=1634128