July 09, 2009
Calorie Restriction Extends Life In Monkeys

After 20 years of waiting (hope you didn't get too impatient) the answer is finally in: This study increases the likelihood that calorie restriction will extend human life too.

MADISON — The bottom-line message from a decades-long study of monkeys on a restricted diet is simple: Consuming fewer calories leads to a longer, healthier life.

Writing today (July 10) in the journal Science, a team of researchers at the University of Wisconsin-Madison, the Wisconsin National Primate Research Center and the William S. Middleton Memorial Veterans Hospital reports that a nutritious but reduced-calorie diet blunts aging and significantly delays the onset of such age-related disorders as cancer, diabetes, cardiovascular disease and brain atrophy.

"We have been able to show that caloric restriction can slow the aging process in a primate species," says Richard Weindruch, a professor of medicine in the UW-Madison School of Medicine and Public Health who leads the National Institute on Aging-funded study. "We observed that caloric restriction reduced the risk of developing an age-related disease by a factor of three and increased survival."

During the 20-year course of the study, half of the animals permitted to eat freely have survived, while 80 percent of the monkeys given the same diet, but with 30 percent fewer calories, are still alive.

Begun in 1989 with a cohort of 30 monkeys to chart the health effects of the reduced-calorie diet, the study expanded in 1994 with the addition of 46 more rhesus macaques. All of the animals in the study were enrolled as adults at ages ranging from 7 to 14 years. Today, 33 animals remain in the study. Of those, 13 are given free rein at the dinner table, and 20 are on a calorie-restricted diet. Rhesus macaques have an average life span of about 27 years in captivity. The oldest animal currently in the study is 29 years.

Those on calorie restriction have a less debilitated old age too. They get less cancer, less insulin-resistant diabetes, less decay in motor control, less decline in motor functions.

What I want to know: Will resveratrol deliver these same benefits in humans without the need to live in perpetual hunger with a gaunt skinny look?

I forgot some of the downsides to Calorie Restriction (CR):

Calorie restriction may seem promising, but it has potential downsides, including constant hunger, sensitivity to cold, weakened immune function and sour mood, says Susan Roberts, professor of nutrition and psychiatry at Tufts University, where she is leading a study on calorie restriction diets.

My guess is that someone on CR will do worse in an accident because their body will have less reserves to draw on. Anyone know if that's the case?

Share |      Randall Parker, 2009 July 09 07:42 AM  Aging Diet Studies

Audacious Epigone said at July 9, 2009 7:48 AM:

What I would be interested in knowing is how calorie expenditure factors into the equation. I'm on a 5,000 calorie a day diet. Am I digging myself an early grave? Does high caloric intake have the same effects on especially active animals as it does on sedentary ones?

Billy Oblivion said at July 9, 2009 11:25 AM:

Reservatol will not deliver the same results. Aging will not succumb to a single-bullet approach (unless you want to consider something like "genetic re-engineering" a single-bullet)

You don't have to "live in perpetual hunger with a gaunt skinny look", there are techniques like Intermittent fasting or planning meals that include a lot of high-quality food with some bulk, low calorie fillers.

If you're eating 5k calories a day and burning 4500 a day, then yes. If you're eating 5k a day and burning at least 5k a day, then yes, but for different reasons. Google "Clarence Bass" and "Art De Vany".

TSM said at July 9, 2009 12:21 PM:

Hey, I'd be interested in calorie restriction, but I have two concerns.

1. I'm less muscular than I'd like to be (6'1", 170). Consequently I work out and am eating about a 3000-3500 calories a day (probably need more). My long term goal weight is ~200.

2. I recall reading that under CR, libido is reduced. That is definitely not desired.

Is there a way to maintain high libido levels and gain muscle mass, or at least maintain it (given that I continue lifting), on a calorie restricted diet?

Fat Man said at July 9, 2009 2:58 PM:

Actually, your life won't be longer, it will just seem like its longer.

as said at July 9, 2009 7:00 PM:

Hi Audacious,

May I ask why you eat half as much as Michael Phelps? Are you a big guy and do you exercise like all the time?


ernest said at July 9, 2009 7:31 PM:

But what about the overall psychological well-being of the animals? Life satisfaction? those would be hard to measure...

Lauri said at July 10, 2009 2:24 AM:

I would like to know does one need to reduce his caloric intake if he is lean and without any "extra" fat in his body.. Are the health benefits there with intaking as much calories as he is burning or does he still have to reduce his caloric intake.

Eating less calories than ones basic usage is, will lead to the body consuming muscles and fat for energy.. Is the correct way to do caloric restriction to let the body eat as much muscles to energy as it will and then just keep the same intake after the body doesn't/can't consume muscles and fat anymore?

I weigh about 67kg and eat about 2000kcal per day. I'm sure that if i reduce my intake the weigh will come of muscles. I'm not sure i would want that. And i don't understand caloric restriction enough to even know if that would benefit my health.

Audacious Epigone said at July 10, 2009 3:30 PM:


I play a semi-pro sport and work out everyday b/w 1.5-2 hours (lift 4x weekly, run stairs 3x, bike 1x, treadmill 3x). I've dropped a little weight over the last three years, to 190 lbs (and 6'1).

Tom said at July 12, 2009 8:31 AM:

Actually, the calorie restriction effect on aging was solved not too long ago...look up work on G. Barja on Pubmed.

It was found amino acid restriction does the same effect, and then it was further found that methionine restriction specifically is the sole cause of the effect.

reason.com said at July 13, 2009 12:25 PM:

From Monkeying Around with the Data on Calorie Restriction?, posted today:

[T]he difference in actual death rates between the dieting monkeys and the free feeding monkeys was not statistically significant.

Food policy blogger, Sandy Szwarc, looks at the reported results at Junkfood Science and finds them severely wanting. Among other things, Szwarc argues:

The lower mortality claimed among the monkeys on the calorie restricted diet were achieved only after eliminating 37% of the monkey deaths. They defined mortality as “age-associated deaths” and eliminated any cause of death they didn’t believe was associated with aging. As the supplemental data explains, 16 deaths from “non-age-associated causes were censored and their age of death used as the time variable in the regression.”

Science doesn’t really work that way. Researchers can’t simply ignore the evidence that doesn’t support their hypothesis. That would be the difference between research done to build evidence to support a hypothesis, from science that is objectively studying a hypothesis...

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