Severe CR starting in young adult mice has produced 60% extensions of total lifespan

Are there any young people or just anyone practicing either Intermittent fasting or CR? Or doing it combined with rapamycin, seems like it would buy the most years for reaching future therapies to reverse aging.


Do you have a paper to reference for the 60% life extension claim? I didn’t think it was that high, and I thought it had to be initiated even younger (though “young adult” is a little vague).

The best place to ask that question regarding anyone practicing is the CR Society:

I’ve tried serious CR for 6 months, its really hard, you’re frequently cold, you’re always hungry, it impacts your social life (going out with friends for dinner is hard), and the results in monkeys were mixed. Its a lot of suffering for questionable outcomes, and only a small percent of people could stick to a CR diet I suspect.


There seems to be evidence in humans, not for maximal lifespan, but for reduction in mortality.

Calorie restriction without malnutrition in World War I and II

Involuntary episodes of CR are not uncommon in human history, but only few of these events were not accompanied by malnutrition, because the local governments wisely enforced food restriction with an adequate consumption of essential nutrient-dense foods. During World War 1 in 1917, Danish men and women were forced to reduce food consumption for 2 years, but with a well-planned and adequate consumption of whole grain cereals, vegetables, and milk. The result of this undesired experiment was an impressive 34% reduction in death rates (Hindhede, 1920). Similarly, in Norway during World War 2, the citizens of Oslo underwent a forced 20% CR without malnutrition (i.e. Norwegians were provided with adequate intake of fresh vegetables, potatoes, fish and whole cereals) for approximately 4 years (1941–45). In this forced experiment, mortality dropped by 30% compared to the pre-war level in both men and women (Strom and Jensen, 1951).

Is it possible that a brief CR episode in life can sustain the benefits, similar to how short-term rapamycin-taking benefits mice for life? How brief is brief? Do we do take the proportionate brief period in mice? That is a long time. Three months of 36 months (mouse lifespan) is eight years in humans (ten percent).


I think the mechanism is autophagy/mitophagy leading to greater cellular efficiency. The cause of this (one cause) is fasting. I am not persuaded that CR beyond this helps.


An example of a study here The retardation of aging in mice by dietary restriction: longevity, cancer, immunity and lifetime energy intake - PubMed done on it showing actually 65% extension (with the most severely restricted group) on top of a healthy normal lifespan, so the 60% is conservative. These WT mice are living over 4 years on the severe group… numbers usually unseen except for longevity mutants.

and @John_Hemming its not just the fasting/autophagy because the groups on a similar fast schedule but more food total did not live as long.

(Make no mistake this kind of restriction is definitely not practical for most people nor comfortable)

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Full study below:

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I do some fasting, but chronic caloric restriction seems painful. I’ve wondered since the days of Roy Walford that with some things, the downside may outweigh the benefits.


I have seen research that indicated it was fasting. However, one would assume that mice can eat too much as well. Hence ad libitum feeding is probably not helpful.

New paper:

Open Access Paper:

Effect of long-term caloric restriction on DNA methylation measures of biological aging in healthy adults from the CALERIE trial

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I’ve been keeping a rough intermittent fasting schedule for the last year. I usually fast 14-16 hours from dinner to lunch the following day. It’s not the most scientific regime, but it lets me get some of the benefits of “feeling hungry” and crank out a bunch of focused work in the mornings.

I drink black coffee with a small square of dark chocolate in the AM, but I don’t consider that breaking the fast – just a quality of life improvement.


This seems like a scientific explanation for the saying:

“Hard times create strong men, strong men create good times, good times create weak men, and weak men create hard times.”

CR + close social connection + sense of life purpose + physical activity = longer life

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Coffee and chocolate = quality of life. Amen to that!

That’s very interesting. Holocaust survivors , after periods of very severe CR to the point of starvation, have been found to live very long lives.

Nir Barzilai studied 750 Ashkenazi centenarians. Am trying to hunt down the data. I suspect many are concentration camp survivors.

I believe that the longest lived Holocaust survivors are all male. This reminds me of the MK study on rapamycin where the highest dosed mice that lived the longest were also males.

Since short term CR provides lifetime benefits, and there is the opinion that rapamycin is a CR mimetic, I am reminded of your earlier post;

And how about even shorter-term, but lifetime CR, like 24-36 hours every six months or so? That would be a study I would recommend to ITP.