A large, long-term study of calorie restriction in rhesus monkeys at the Wisconsin National Primate Research Center has shown that the diet prevents diabetes and may reduce the risk of arthritis and other age-related diseases. The leaner monkey on the left is on the restricted diet, the one on the right is on a normal diet.
An ongoing study at the University of Wisconsin-Madison in which rhesus monkeys are being fed an extremely calorie-restricted diet gives preliminary evidence that the regime prevents age-related diseases