Monkeys Eat Less, Live Longer—But Why?


“Scientists have long known they could increase the lifespan of mice, and […] worms, flies—with deep, long-term cuts from normal consumption.” (Monkeys live longer on low-cal diet; would humans? by Lauran Neergaard AP Medical Writer | July 9, 2009)

Question: How normal is a laboratory animal’s “normal consumption” when compared to a free animal’s consumption? How does a laboratory chow for rhesus monkeys compare to their natural diet—leaf for leaf, bug for bug, fruit for fruit?

In a study headed by Dr. Richard Weindruch, a University of Wisconsin-Madison professor, 76 rhesus monkeys were fed “a normal diet of captive monkey, a special vitamin-enriched chow plus some fruit treats.” Half the monkeys had their chow intake cut by 30 percent. So far, 13 percent of the monkeys in the cut-chow intake have died of age-related diseases versus 37 percent of the monkeys on the regular diet.

Also, the monkeys on the lower-calorie diet (less chow) had “less than half the incidence of cancerous tumors or heart disease of the monkeys who ate normally [had their fill of chow—TK].”

Question: Is it really only the calorie restriction that made the monkeys healthier or is the lab chow so vile, the more they eat it, the sooner they die?

Request for help:

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7 Responses to “Monkeys Eat Less, Live Longer—But Why?”

  1. 1 Charles

    Great question, Tom!

    I think it is true that calorie restriction has beneficial effects. That has been shown in a number of studies. But you’re right to question whether it’s the result of the calories per se, or just cutting out some of the crap, or reducing it below harmful levels.

    Some anthropological research, for instance, has shown that there is a plateau effect in terms of the damage that the modern western diet creates. When consumption of refined carbohydrates and industrial oils gets above a certain percentage of the diet, the “diseases of civilization” (heart disease, gout, diabetes, etc.) start to appear in the population.

    We also find that when people go on very low-carbohydrate diets, their calorie consumption tends to drop by 30% or so naturally. So are the proven benefits (better lipid profile, reduced inflammation, decreased insulin, reduction of body fat, etc.) of the LC/Paleo diets the result of the reduced calories, or the result of the reduced sugars and grains? I guess I would argue more strongly for the latter, but it would be really interesting to design a study that would examine that particular question.

    So for the monkey studies, we need to give monkeys diets more reflective of what they might eat in the wild, then reduce the calories of one group, and see what happens.

    And we can do the same for people with a more natural, paleo-type diet.

  2. More on the study at:

    Calorie Restriction: partial restoration, not enhancement

    So, indeed one may sum up this study by paraphrasing my original (and only rhetorical) question thus:

    The scientists fed monkeys a chow so vile, the more monkeys ate, the sooner they died.

    It takes Dr. Harris very many words to say the same thing.

    His justification of the chow’s composition damns the researchers. How dull does one have to be to feed animals slow poison and then call the study “Caloric Restriction Delays Disease Onset …” and not “Poison Restriction …”? Dr. Harris says that the researchers devised the chow in the 1980’s when they thought this was “a very healthy monkey diet.” So in the 1980’s the researchers didn’t know what rhesus monkeys eat in the wild?

    I think that researchers of similar quality have devised the USDA Food Pyramid and many more government-pushed dogma on health.

  3. 3 CSta

    In light of this blog entry and your immediately preceding one, in which you cite to “PaNu, paleolithic nutrition – duplicating the evolutionary metabolic milieu,” what should the macronutrients percentage be? The PaNu guy says 65-70% fat (the vast bulk of which should be “healthy animal fat”), 20-25% protein, and 10% carbs (berries and vegies), which turns the USDA food pyramid up-side down. In his Fats and Oils article/entry, the second comment from Chris W states that combining saturated fats and carbs (even small amounts) “can cause problems,” so if you do the PaNu thing, you have go full force; you can’t just do it “a little.”

    I don’t want to wind up like the “over fed” monkeys. My maternal grandmother lived to 100. I’d like to do the same.

  4. Dr. Kwasniewski’s books such as Optimal Nutrition give a good advice and many recipes.

    Another way is to begin with Barry Sears’ Zone recipes and then, over a few weeks, experiment with macronutrient ratio, say, increasing the fat while reducing the carbs, or even the protein. You will know if you hit the right ratios when you can go more than four hours without needing to eat–and I think the longer the better. Also keep in mind that a good meal (good foods, right proportions) energizes, a bad meal stupefies.

  5. 5 CSta

    There is a substantial difference of opinion on the proper ratio of saturated fat to total fat in one’s diet. Will experimenting with my diet reveal how much of each different type of fat I should eat?

    If not, what’s a consumer to do with such varying opinions?

  6. Will experimenting with my diet reveal how much of each different type of fat I should eat?

    Yes. “You can observe a lot by watching”—Yogi Berra

    If not, what’s a consumer to do with such varying opinions?

    Check the sources and look at the experts. The way they look will tell you a lot about the value of their expertise. Again: “You can observe a lot by watching”—Yogi Berra

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