Eating less won’t make you live longer

Calorie restriction has been shown to extend life in several types of animals including worms, flies and mice. The question was whether it would work on humans. Given that such an experiment would take decades to conduct and carry a lot of ethical baggage,  scientists turned to monkeys and started experiments in the late eighties.  Well the results are in and the answer is probably not. A study just out in Nature (link here) finds that rhesus monkeys that were given a reduced calorie diet did not live longer. This contradicts a previous study from the University of Wisconsin published in Science in 2009 (link here) which did show caloric restriction extended life of monkeys.  However, in that study, monkeys that died due to causes that were deemed unrelated to aging were not included.  Here is a New York Times summary. There are some people who are currently limiting their diets in an attempt to live longer so perhaps we will have some unofficial data points on humans in few decades.  My guess is that there will not be a net increase in humans since lifespan is a complicated thing and there are always tradeoffs.  Caloric restriction may be protective in some aspects but it may also be detrimental in others.

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4 thoughts on “Eating less won’t make you live longer

  1. 2012: 34 monkeys, P = 0.003.

    2009: 76 monkeys, P = 0.03

    Not saying that I’m sanguine either way, but since studies of other animals with larger populations tend to align with the 2009 study, and since both 2009 and 2012 studies are pretty much tumorous balls of confounder layered upon confounder, I can’t feel confident that the hypothesis is much impacted (either way) by the two 2009 and 2012 monkey studies.

    I wonder, are you also more impressed by the higher-n studies of smaller animals, or the findings of reduced atherosclerosis in large animals like humans, or by the other, higher n studies of measures of variables other than longevity in large mammals? I mean, longevity is a single, nuance-less data point, and almost certainly subject to unplanned, experimental confounding in experiments on such unpredictable, expensive animals.

    This reminds me of James’ paper, BTW.

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  2. I agree that calorie restriction may have some beneficial effects that could help extend lifespan but as you say it is a pretty blunt measure. I just think there will be no noticeable effect in practice because of the many confounders.

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  3. It may be related to the way the diet was carried out.
    It has been conjectured, and shown in some animals, that a period of fasting (ex. 8 hours a day intermittent fasting) can prolong life.
    Maybe the older study’s diet involved longer periods between meals that could have sparked off that effect.

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