The monkey on the left has been on a caloric restriction diet for over a decade.
Caloric restriction (CR) has been shown to extend the lifespan in a range of species, but the most exciting study has been the one on Rhesus monkeys. The study, led by Weindruch and Colman, has been going on for more than 20 years now.
Last week, new results regarding the monkeys were reported, and New York Times published an article discussing whether they might be translatable into humans. Dr. Weindruch, quoted in the article, seems to be very optimistic:
The researchers say that now, 20 years after the experiment began, the monkeys are showing many beneficial signs of caloric resistance, including significantly less diabetes, cancer, and heart and brain disease. “These data demonstrate that caloric restriction slows aging in a primate species,” they conclude.
I'm fairly confident we will eventually see a statistically significant increase in maximum lifespan in the monkeys, but I think it's somewhat premature to state it as a fact while the study is still running. I guess 20 years of waiting for conclusive results is a lot even for a patient scientist.
Looking at the pictures of the calorie-restriced monkeys next to the normally fed monkeys, it's evident that something good is happening – or rather, something bad is being prevented. The CR monkeys do look healthier and, well, younger. Here's a couple of more pictures (with the calorie-restricted monkey on the left):
All in all, for everyone out there doing CR this study seems to be positive news. For many others, this is just the first step, however. Learning how calorie restriction works will perhaps be even more important than seeing that it works. Drugs and treatments that target the same pathways can then be developed without the need to reduce calorie consumption dramatically. The article mentions resveratrol as a possible substance to replace calorie restriction:
Few people can keep to a diet with 30 percent fewer calories than usual. So biologists have been looking for drugs that might mimic the effects of caloric restriction, conferring the gain without the pain. One of these drugs is resveratrol, a substance found in red wine, though in quantities too small to have any effect.Dr. Weindruch said the study data offered “very encouraging” signs that resveratrol could duplicate in people some of the effects of caloric restriction.
It's important to note that "duplicating some of the effects of caloric restriction" is not the same things as extending lifespan. Yes, it may help people with diabetes live longer, but there's no evidence out there that shows resveratrol increases maximum lifespan in healthy humans or animals.
Not to bash on resveratrol, though; I think it's one of the most interesting supplements out there. It just won't make us live to see a thousand, despite what some people would have you believe.
For more information on caloric restriction and resveratrol, see these posts:
Anti-Aging in the Media: 60 Minutes on Resveratrol
Caloric Restriction Improves Memory in the Elderly
Green Tea Increases Weight Loss during Caloric Restriction in Rats
Anti-Aging in the Media: Houston Press on Caloric Restriction