The science of calorie restriction just got a lot more complicated.
Rhesus monkeys fed experimental low-calorie diets didn’t live any longer than their high-calorie brethren, a result that conflicts with a 2009 report of long-lived, extra-low-calorie monkeys.
That had been the first demonstration of extended lifespans in primates, not just lab rodents, and raised hopes of the diet being a dinner-plate fountain of youth. The new findings seem to challenge that notion, though they’re far from conclusive.
More fundamentally, the findings pop the lid on a roiling scientific back-and-forth over calorie restriction’s effects and mechanisms, a matter of vigorous contention that’s belied by popular notions of the diet as a simple, straightforward longevity hack.
“From the beginning, there have been people who were true believers in the effects of calorie restriction in every single species,” said Rafa de Cabo, a National Institute on Aging gerontologist and co-author of the new study, published Aug. 29 in Nature. “Often attention wasn’t paid to data showing that in some cases calorie restriction wasn’t good, or didn’t produce the effects it should have.”
De Cabo’s experiment started in 1987, right around the time as another, similar experiment at the University of Wisconsin. Both groups wanted to know whether calorie restriction — cutting intake by up to 40 percent below what’s typically considered healthy — would have the same health-protecting, life-prolonging effects in primates that it seemed to have in lab animals.