A study, started in 1989 involving rhesus monkeys has provided the first strong evidence that caloric restriction slows the aging process in primates.
A diet that's nutritionally adequate, but provides 30 percent fewer calories than normal has been shown to extend life span and delay the onset of age-related diseases in other animals, including flies, worms, and rodents. Because studies on primates take much longer, the benefits had not yet been demonstrated. Researchers at the National Primate Research Center at the University of Wisconsin-Madison report in July 2009 that in rhesus monkeys that had a caloric restriction diet begun in adulthood reduces risk of the most common age-related conditions, like diabetes, cancer, heart disease, and brain atrophy, by 30 percent.
The research involved 76 monkeys, half of them on the diet. The 33 surviving monkeys have reached old age. Thirty-seven percent of the monkeys on a normal diet have died of age-related diseases, compared with just 13 percent of the monkeys on the restricted diet. Reminds me of the Jack Benny line when asked, "Your money or your life?". . . "I'm thinking about it."