Early Calorie Restriction Extends Life in Mice
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Reducing calorie intake for a comparatively short period of time very early in life is here shown to have life-long effects in mice. This provides more insight into the way in which metabolism in shorter-lived mammals has evolved to react to temporary famine conditions, producing more robust health and up to 40% longer life spans for life-long calorie restriction. It is interesting that even a short period of low calorie intake early in life can have the effects noted in this study.

We humans share the same evolutionary heritage of nutrient sensing mechanisms intended to alter our metabolic processes based on calorie intake, and the beneficial effects of calorie restriction on measures of health are quite similar to those in mice, but calorie restriction doesn't extend our life by anywhere near the same proportion. The consensus in the scientific community is that calorie restriction will extend human life by perhaps 5% or a little more. On the other hand, the health benefits are greater than those produced by any presently available medical technology or lifestyle choice.

The action of nutrients on early postnatal growth can influence mammalian aging and longevity. Recent work has demonstrated that limiting nutrient availability in the first three weeks of life (by increasing the number of pups, in the crowded litter (CL) model) leads to extension of mean and maximal lifespan in genetically normal mice. In this study we aimed to characterize the impact of early life nutrient intervention on glucose metabolism and energy homeostasis in CL mice. In our study we used mice from litters supplemented to 12 or 15 pups and compared those to control litters limited to 8 pups.

At weaning and then throughout adult life, CL mice are significantly leaner and consume more oxygen relative to control mice. At 6 months of age, CL mice had low fasting leptin concentrations, and low-dose leptin injections reduced body weight and food intake more in CL female mice than in controls. At 22 months, CL female mice also have smaller adipocytes compared to controls. Glucose and insulin tolerance tests show an increase in insulin sensitivity in 6 month old CL male mice, and females become more insulin sensitive later in life. Furthermore, β-cell mass was significantly reduced in the CL male mice and was associated with reduction in β-cell proliferation rate in these mice. Together, these data show that early life nutrient intervention has a significant lifelong effect on metabolic characteristics which may contribute to the increased lifespan of CL mice.

Link: http://dx.doi.org/10.1152/ajpendo.00031.2014


"Following a vegetarian diet could mean you live more than nine years longer than you might by consuming meat based diets, according to new research findings."


It is said that it is possible reduced methionine may be behind the lifespan benefits. While not all vegans supplement with b12 and thus some may suffer deficiency, which could affect their health.

Combined with moderate exercise even telomere length appears to reverse to a longer more youthful profile, at least in measured cell types.

If indeed methionine reduction is the cause of vegans greater lifespan, it would be a CR mimetic intervention, and greater reduction may or may not yield even greater effect on lifespan.

Posted by: darian s at May 14, 2014 4:44 PM


I had a two-part question:

(A) Are the benefits of CR accumulated throughout the day either (A) during the daytime while you are awake and as you implement the diet, or (B) accumulated throughout the day but you only gain the benefits when your metabolism is slowed while you sleep? (I am sure that this can effectively be said to be a scaled down version of daily “intermittent” dieting.)
(B) That being said, whether day-to-day intermittent dieting works or not, would I gain any benefit from successfully keeping my caloric intake down all day, but then “stuffing myself” before I go to sleep. (When I say “day-to-day intermittent, I mean one day I practice CR, and the next I don’t, ect.”)

My thoughts on the first part came from the idea of memory storage and how your experiences throughout the day will store short-term memories but they will acquire a more “permanent residence” in long-term memory during certain stages of sleep.

Posted by: Donald at May 18, 2014 6:52 PM

@Donald: I have no idea as to the answer to your question. I'm not aware of any research showing differences in the outcome from intermittent fasting or calorie restriction due to differences in the distribution of calorie intake during the day, but it may exist.

Intermittent fasting has been shown to produce health and longevity benefits in laboratory animals even when there is no overall calorie restriction, but these seem to be smaller than the benefits when there is calorie restriction.


Intermittent fasting certainly produces benefits in humans. It isn't as well researched as calorie restriction but that will probably change in the years ahead.



Posted by: Reason at May 18, 2014 8:09 PM


Thanks, that did shed a little light on the subject. Also, I had two more quick questions.

(A) How would I go about figuring out my personal caloric needs? Would that not require actually going to a physician and having several tests done? Or would a little research on Google be sufficient?

(B) When comparing the health benefits of calorie restriction versus keeping a low fat ratio, can each be said to hold the same gains as the other? For example, I see in my genetic lineage a predisposition to burning calories off fairly easily. It doesn't matter how much I eat, I will not gain a pound. So, if I practiced CR, would I be wasting my time and effort?

Posted by: Donald at May 19, 2014 10:35 PM

@Donald: For questions on practicing CR, I suggest you sign up for the CR Society mailing list. That is definitely the best place to go for answers, given that many of the folk on the list are involved in the human studies and some have written books on the topic.


Low fat levels are probably a part of the reason by CR produces health benefits, but they are by no means all of it. You have to eat less to trigger metabolic alterations that kick in based on sensing low levels of methionine, for example. There are no doubt other line items as well.

Posted by: Reason at May 20, 2014 6:12 AM
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