Much work over the past few decades has shown that caloric restriction can increase longevity and reduce susceptibility to a variety of illnesses. However, that work had been performed in worms, flies, rodents, and other non-primates. To date, no studies had been published that examined the effects of caloric restriction in primates. There are several ongoing studies of caloric restriction in primates (even one in humans I believe, though I think that particular study is quasiexperimental in nature), however due to the longevity of primate species it looked as though we were in for a long wait.

Last Thursday the Globe and Mail published a spot on a study that had started in 1989 that tracked the effects of caloric restriction in rhesus monkeys. Caloric restricition in this study was defined as 30% of free-feeding levels of consumption; all calorie-restricted monkeys were fed balanced diets. Enough of the result are in for the researchers to make some preliminary conclusions. Here is the general finding: "Eighty per cent of the monkeys on the calorie-restricted diet are still living, compared with just half of the non-dieters."

Dramatic. And it is consistent with the findings in non-primate species. We will have to wait to see how long the remaining monkeys live and also to see the results of the other primate studies that are underway.

Here is a link to the actual paper, which was published in the journal Science: The paper. If for some reason you can't access that link, here is a link to the PubMed listing: The listing. Some of the images published in the actual paper are quite dramatic (and hopefully representative). For example, below you can see a free-feeding monkey at 27.6 years of age on the left, and an age-matched calorie-restricted monkey on the right.