Calorie Restriction and Life Extension

Every study done on any species has shown that calorie restriction expands lifespan.  A recent study (via David Lat's Facebook) was done on earth worms:

Sometimes it’s not what you eat, but when you eat it. At least when it comes to longevity diets. For some time, scientists have known that animals kept on a strict diet live longer than their well-fed peers. But this Methuselah meal plan is no ordinary just-say-no-to-that-second-slice of pie kind of diet. To reap the life-extending benefits, some of these animals cut their calorie consumption in half. Such a diet might be do-able for captive mice and monkeys, but it would be a tough sell for people.

Then, five years ago, studies in mice suggested that intermittent fasting would work just as well. These mice abstained from eating every other day, and lived longer then their gluttonous comrades—without really skimping on the total calories they consumed.

Now, scientists at Kyoto University have found the same thing in worms that fasted every third day. And they found a gene that regulates the effect, results reported in the journal Nature. Like the mice, these fasting worms did not cut their total calorie intake. But they boosted their lifespan by 50 percent, and showed fewer signs of physical decline than their peers. So go ahead, enjoy that extra slice of pie. Because tomorrow’s another day. To not eat.

Of course, neither modern medicine nor the American Medical Association will trumpet these results.  There is no expensive drug to sell.  And how many people want to hear that eating less is the fountain of youth?

I certainly respect people who make a cost-benefit lifestyle choice about their weight.  If you're willing to die a few years (or decades) sooner because you like to eat, great.   How dare I or anyone else suggest you live your life otherwise? 

But the debate over whether calorie restriction will increase lifespan really is over - and probably has been over for years.  The only open questions are, among others, whether intermittent fasting is as good as steady calorie restriction; and whether one can realize the benefits of calorie restriction through protein restriction:

"That was puzzling because it was the first time we hadn't seen agreement between mice and rats on calorie restriction and humans on calorie restriction," Dr Fontana explained. "But we know there are two major influences on IGF-1 levels: calorie intake and protein intake. So we decided to look at the influence of protein."

Dr Fontana and his associates next examined a population of strict vegans who consume no animal products, which results in a lower protein intake than most people, including those who practice calorie restriction. "The vegans had significantly less circulating IGF-1, even if they were heavier and had more body fat than CRONies," Dr Fontana stated. "Protein in the diet seemed to correlate with the lower levels of IGF-1. The strict vegans took in about 10 percent of their total calories from protein, whereas those on calorie restriction tended to get about 23 or 24 percent of calories from protein."

There are lots of interesting issues regarding calorie restriction.  Whether it works?  That has gone the way of the flat Earth theory.

Incidentally, if you're interested in calorie restriction, or life extension, or simply living a better life, check out the Life Extension Foundation.  I've always had a sense of my own mortality, and thus have been a member since I was 22.

Comments

[Aaron]

"I've always had a sense of my own morality"

Sure, as evidenced by your WWJD bracelet. ;-)

But seriously, in humans, we're talking what? Life extension by two or three years, maybe? In terms of longevity and quality of life, how does that contrast with, say, a balanced diet and a good exercise regimen?

[Mike]

There are (at least) two ways to look at it..........

1) Disease prevention. Who knows what will get us in our 40s or 50s? Generally a good diet can prevent some of the stuff that gets us "young."

2) In monkeys, calorie restriction is adding up to 10%. So for someone like you or me, that could be 7-8 years.

Neither of us are old..... But when we are, we won't want to die. So it's hard to discount even 2-3 years. How many old men (in good health) wouldn't give up all or most of their money for just a little more time?

[Mike]

how does that contrast with, say, a balanced diet and a good exercise regimen?

That is another interesting question. I don't know. No one does. Right now, that's my way of life. I'm not doing CR..... yet.

I will be soon enough, though. Probably when I hit 35-40.

But it's a balance. If you've ever seen someone who does full on CR, you'll cringe. Me on CR would be about 140 pounds. Gross. I, quite frankly, would not want to go through life like a weakling. I'm willing to give up a couple of years of lifespan.
But I don't look nearly as good as I would if I used steroids. I have a nice sweet spot of 185-195. Not big, but not a waif.

So, yeah, it's a balance. I think, though, every balance should be fully informed.

I know that I'm killing myself early to live a certain way. I'm not in denial about my choices.

So I only post things like I did so others can make fully informed choices. Live long or die young.... That's not my choice to make for anyone else.

[matthew Lake]

A few things.

Calorie restriction is known to extend lifespan in all organism, and usually in proportion to the degree of calorie restriction. There is only theoretical evidence by a few researchers that claim CR will only give 2-3 years of extra life. This is not even evidence against CR, just speculation backed up by a very little hard science. Whereas the overwhelming evidence suggests that CR is working.

Also on the IGF-1 issue. There is no evidence that CR will lose its benefits if IGF-1 is increased by a higher protein CR diet. In animal studies when they feed them upto 50% of calories from protein they actually live longer on CR, and maximum lifespan goes up even more. Again this story is not evidecne against CR working in humans.

As for the monkey experiments. There have been a few going on. One of them was completed and they they found that on a reduced calorie diet, which the CR monkeys had their calories restricted by 30% they lived on average 30% longer. This wasn't even a true 'anti aging calorie restriction diet' as are done in rodents. Just merely obesity avoidance. The CR animals managed to live to 32 years of age (which is 96 human years) and the ad lib group lived to 27 years (which is 75 human years). So the ad lib group wasn't really abnormally short lived. So in human terms this is like gaining a 21 year increase in human lifespan by 30% CR.

As for intermittent fasting. There is still not enough good evidence that it works in the absence of calorie restriction in mammals. So it's still CR, not resveratrol, intermittent fasting that is the most likely to work.

You're welcome to check out my CR blog. I've been on CR for a few years. The younger you start CR the more you retain your youth. Hey I mean, now that I'm 24 and been on CR a while I always get mistaken for being 16 all the time. Seems like I stopped the appearance of aging at least Haha. So if I die at 80, then at least i'll look young :p

[Matt]

i mean 25 years not 27. sorry!