Dieting Monkeys Live Longer

We’ve known for a long time that severe caloric restriction can dramatically increase the lifespan of mice, but needless to say, mice are not people. Now, researchers have reported not only greater longevity in rhesus monkeys on restricted diets, but less disease and less brain shrinkage as well. Rhesus monkeys aren’t people either, but they’re quite a bit closer to us than mice.

Both monkeys are elderly (27 years), but the one on the right is the dieting monkey

We’re not talking a Jenny Craig diet here–these monkeys were severely restricted to 30% of the calories consumed by the free-feeding rhesus. That 30% number is mind-boggling. In my old rat-lab days at UCLA, we would bring rats down 20% to motivate them to bar press for food. They were plenty motivated, and were so close to starvation that if they missed one day of food they would die (I explained to my students in learning lab that if they skipped feeding for a day, I’d flunk them). So I’m not sure how practical this 30% level of restriction would be for people. Still, if you compared the calories I’m eating today to the calories I consumed as a young adult, when dropping 5 pounds because my jeans were tight meant skipping my evening ice cream or eating fewer cookies during the afternoon for a couple of days, I’m probably down by at least 50%.

These monkeys experienced a lifetime of restricted eating, so it’s hard to say how these data affect those of us who kind of caught on to the obesity epidemic thing a little late in the game. Better late than never, I suppose.

This study also suggests that we should take another look at BMI. Based on my personal experience with Jenny Craig, you do not reap all the health benefits of losing weight until you are really pushing the envelope on the low side. I have much better health at my 19.5 BMI than I did at what is considered a “healthy” BMI of 24.9. At my height, that’s a margin of 30 pounds, and the idea of carrying around a 30 pound sack all day doesn’t sound like fun. Improvements in health also take time. As I wind up my second year on maintenance, I am experiencing new health benefits that I didn’t enjoy even last year. I have not taken a single allergy pill all year–haven’t needed to. It is rare for me to NOT get 8 hours of uninterrupted sleep, but that almost never happened in my chubby iteration.

It’s also time for the apologists to get real. It is NOT okay to be fat. We have spent so much time worrying about “body dissatisfaction” that we’re afraid to tell people that they’re killing themselves with pizza and beer.  A dietician interviewed by the BBC said “People would have to weigh up whether they are prepared to compromise their enjoyment of food for the uncertain promise of a longer life, and a life which could be dogged by all sorts of problems – including osteoporosis.” Oh come on, it’s not either/or. We eat very well (see Mr. F’s recipes)–we just indulge once or twice a week, not every day. And guess what–when your system is not clogged with junk, you enjoy food a whole lot more!

We have to stop telling people diets don’t work. They do.  Check out the many successful dieters who have joined the National Weight Control Registry (I am very proud to be a member). What people need is more information about how to control their weight in healthy ways, not some defeatist talk that says it can’t be done. Jenny Craig worked for our family (we collectively have lost an NFL lineman), but Nancy Kennedy describes the many ways people succeed in her blog Thirty Ways. Do you want to look like the monkey on the right instead of the one on the left? Start today!