Hey, you! Want to live longer? Put down that cheeseburger! And you’ll probably have to skip a meal every day too.
Eating less has been proven time and again to prolong the life of many organisms by as much as 40 percent. The only problem is that all of those organisms include species like yeast and worms; the shorter the lifespan, the easier it is to determine effects on aging and mortality rates.
But being as interested in living longer as our species typically is, there have been a couple of major studies looking to see if this general idea can be applied to primates. By a couple, I mean two: one by the National Institute on Aging and the other by the University of Wisconin.
In 2012, the former issued a report saying that caloric restriction didn’t have any effect on 120 monkeys participating in the study. You can pick up that cheeseburger again. Just a couple of months ago, however, the University of Wisconsin published results saying that cutting 30 percent of your caloric intake can reduce your risk of death by as much as three times.
Put that cheeseburger down again.
Why the contradictory results? As always, the answers are in the details. Richard Weindruch, one of the founders of the Wisconsin study, has a few theories.
For one, the Wisconsin study didn’t begin restricting the monkeys’ diets until well into their adulthood after their initial baseline for food consumption had been determined. In contrast, the NIA study started them off early without ever really getting an idea for how much they monkeys would eat left to their own devices. What’s more, the NIA kept all of their monkeys on a regulated diet, whereas the Wisconsin study let the control group eat however much they wanted.
Weindruch believes that, because of these two facts, all of the NIA monkeys were actually on a restricted calorie diet, some of them were just on a stricter one than the others. And because of this, they all reaped the benefits of eating less.
Supporting evidence includes the fact that at all points in the study, the NIA monkeys weighed less than Wisconsin’s. Even if the control group only had their diets restricted by 10 percent due to Big Brother’s control, maybe that’s enough to see the benefits? Plus, a handful of the NIA monkeys not on the “restricted” diet lived past 40 years of age.
“Heretofore, there was never a monkey that we are aware of that was reported to live beyond 40 years,” Weindruch says. “Hence, the conclusion that caloric restriction is ineffective in their study does not make sense to me and my colleagues.”
The dispute isn’t likely to be resolved anytime soon, either. The Wisconsin study included 76 monkeys tracked over 25 years—quite the undertaking. Any volunteers out there to give it a mulligan?
And besides, cutting calories by 30 percent sounds like an awesome idea, until you realize just how much that is. Let’s say you’re currently taking in 2,000 calories a day—not a ton for a 190-pound man like myself. You’d have to drop to 1,400 calories a day, which is barely enough for three 600-calorie meals.
Personally, I’d never make it. I’m pretty sure I’d shrivel away and die. But you’re welcome to give it a shot if you want.
As for the researchers, they’re not suggesting anyone start cutting their calories significantly either. Instead, they’re more interested in trying to figure out what the biological mechanisms are behind the effect. Perhaps they could recreate the benefits with certain signaling drugs rather than having to actually cut calories?
Pick up that cheeseburger again.
The study, “Caloric restriction reduces age-related and all-cause mortality in rhesus monkeys,” was published in Nature Communications by Weindruch; Rozalyn Anderson, assistant professor of geriatrics; Ricki Colman, senior scientist at the Wisconsin Primate Center; and Mark Beasley and Sterling Johnson.