by Marion Nestle
Aug 30 2012

Does starvation increase longevity? Not in monkeys.

The New York Times front page today has a report of a long-term study at NIH of severe calorie restriction in Rhesus monkeys.  It found that calorie restriction did not extend the monkeys’ lifespan.

I’m not at all surprised.  My co-author and I reviewed the literature on calorie restriction for a chapter in our book, Why Calories Count.

The new study makes news because it contradicts a study done in Wisconsin showing that severe calorie restriction extends life.  Severe means 25% to 30% fewer calories per day that are needed to maintain normal body weight.  I’d call this a starvation diet.

An editorial accompanying the report of the study in Nature attributes the difference between the results of this NIH trial and the Wisconsin study to a difference in dietary composition, suggesting that calories differ in their effects.

Not necessarily.  The Wisconsin study allowed the control monkeys to eat a lot of junk food and they were fatter than normal.  The NIH study restricted calorie intake in its control monkeys so they maintained normal weight and were healthier.  This is the simplest explanation of the difference.

Studies in rats, mice, and many other animals show that calorie restriction extends life.

But what about primates?

Starvation can hardly be good for health.  It causes weight loss, of course, but also a host of physiological and psychological problems.  These were extensively documented in humans during World War II in Ancel Keys’ Starvation studies.

The relationship between BMI and human longevity has been examined in several recent studies, all of which show similar results: Longevity is best associated with BMIs in the range considered normal or slightly overweight.  Above that range—but also below it—mortality increases.  

Being underweight is associated with higher mortality.

A Canadian study provides this example:

And one from the National Cancer Institute provides another:

The bottom line?  Eat a healthy diet and balance calories to maintain a healthy weight within that range.

  • It appears we always report on and miss the point:

    It’s not about longevity. It’s about quality of life during our long lives. Thanks to medical advances (surgery, pills, and more), whether you are thin or fat, we are living much longer.

    However, the real issue is … do you want to be a part of the vast medical industrial complex? Unfortunately, because we choose to eat the Main Street Diet, we are inclined to participate in the MIC.

    Ken Leebow

  • It looks like slightly obese live about as long as the “normal or slightly overweight”.

  • If the ONE study you cite had come to a conclusion with which you did not agree, you would have dismissed it as ONE study. But, since it reinforces your already-held bias, you regard it as “proof.”

    There are several studies showing that CR *does* increase lifespan, even in primates. And there are several more that show remarkable increase in lifespan from partial CR (periodic fasting). I found the evidence for periodic CR convincing enough to try alternate-day CR on myself, and I did get some benefit, although I had to tweak things a bit before I found the results really satisfying.

    Despite your wish to believe so, the science is far from “settled.”

  • Looks like overweight is the new normal. Maybe we should extend the term normal to include a wider ranger of BMI. The evidence is there.

    Also, funny how Ancel Keys is still relevant and his work keeps coming up time and again.

  • Fg

    Ethically do we really need to starve monkeys? I think there are a large sample size of humans wh voluntarily fast and could be used to be studied…

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  • Allie

    I attended an NIH lecture the other day and it was proposed that the reason the mortality rate curves upward for low BMI folks too is that this part of the curve contains a disproportionate amount of people who have lost weight as a byproduct of being ill.

    Overall I simply agree that it is not about longevity of life but rather quality. If I could pick between tacking an extra 15 years of malaise-filled life onto the end or being healthy/happy but living not as long I’d choose the latter.