Caloric restriction extends your life, but may make you stupider


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Okay, that’s not really a fair headline or a good summary of the research I’m describing (which is a neat study by researchers at Princeton, explained in an excellent and detailed press release). But I have to admit, I’m not always perfectly neutral — like everyone, I prefer to see some results more than others. And research into caloric restriction is a good example: there’s been plenty of evidence over the past few years of the age-defying benefits of starving yourself:

To date, caloric restriction has been observed to extend lifespan in every organism tested, including worms, mice and monkeys, [Princeton prof Coleen] Murphy said. While the reasons for this are still under investigation, scientists generally believe that the benefits of caloric restriction go well beyond preventing diseases associated with obesity, such as heart disease and diabetes, Murphy added. It appears that limiting food intake actually slows the aging process.

In general, I’m used to leafing through studies and press releases that give me a nice pat on the back. Aerobic exercise is good? Super, I do tons of it! Eating lots of fruits and vegetables is good? Fantastic, I do pretty well on that front. But caloric restriction? That’s the antithesis of everything I stand for, which is doing ridiculous amounts of exercise and consequently being able to eat more or less until I get bored with no ill effects — or at least, no ill effects that I knew of until the emergence of this idea that eating less slows down aging.

So you should read the press release for yourself, and judge its merits in an unbiased manner… but here’s what I took from it:

Young worms whose calories were restricted had normal short-term memories, but their long-term memories were severely impaired; the memories faded within 24 hours, as opposed to 40 hours in normal worms.

(40 hours in worm time corresponds to about 15 people years.)

Now, the study has a lot more to say. While caloric restriction impaired long-term memory, the (impaired) memory abilities didn’t decline as much with old age as they normally do. The study also investigates how insulin-signalling pathways affect longevity and cognitive function (this appears to operate independently of the calorie-restriction effects). So there’s a lot of on-the-one-hand-this, on-the-other-hand-that going on. But it’s the first sign I’ve seen that caloric restriction, even if it extends life, may have some significant downsides:

“The assumption in the field of longevity research has been that organisms able to live longer will function longer as well,” said [Murphy]. “It seems we need to revisit that.”

3 Replies to “Caloric restriction extends your life, but may make you stupider”

  1. “Eat more broccoli”, my wife always tells me, “you’ll live forever!” “No”, I always answer, “it just seems like forever.”

    Or, in context of this story, “the flame that burns twice as long burns half as bright.”

  2. Ahhh, but what about the pesky confounders?

    “The other mutant has a genetic defect that makes it difficult for the worms to ingest food, forcing the animals to eat less.”

    I’ll admit I (also?) didn’t read the study, but who knows what might be linked or also come along with that mutation.

    It’s possible that since the process of eating was difficult (or in other words, semi-painful, or at least less pleasurable), the association between butanone and food wasn’t as strong in the first place, and therefore more easily lost.

    I wished they had used something other than food-finding to measure long-term memory.

    So, I’ll have to leave with every researcher’s favourite comment: “Needs more research”!

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