Dr. Linda Patridge and colleagues of University College London have discovered that the effects of calorie restriction for life extension on fruit flies is remarkably short-lasting.
In a detailed demographic analysis of life and death among 7,492 fruit flies, published today in Science magazine, Dr. Partridge and her colleagues discovered that the protective effect of dieting snaps into place within 48 hours, whether the diet starts early in life or late. Flies that dieted for the first time in middle age were the same as flies that had been dieting their whole lives. But the effect can be lost just as quickly. Flies that dieted their entire lives and then switched, as adults, to eating their fill were the same two days later as flies that had never dieted.
It has been thought that Calorie Restriction must work to increase life expectancy by slowing the gradual accumulation of damage. Therefore the length of time on the Calorie Restriction diet was expected to determine its total life-extending effects. At least in fruit flies there do not appear to be extended benefits once the fruit flies are taken off the diet. This is surprising.
By Randall Parker at 2003 September 19 01:28 AM Aging Reversal | TrackBack"If this works in humans, then it means that from the time a person starts on a restricted diet, they'll be like individuals of the same age who were always on that diet. Their prospects of survival are the same."
That would be so annoying for the guys who've been on the diet their whole lives.
The good news is I can pig out for another couple of decades.
BTW, Aubrey de Grey does not think that CR will yield an extension in life in humans that is as great percentage-wise as seen in some other species. You can see his arguments in some sci.life-extension posts (note my link to sci.life-extension on the right side of my main page) where he explains some of his thinking on this. The CR practitioners are none too happy with his arguments. But if he's right then CR is going to extend human life by at most a year or two.
This is inconsistant with the well established and often quoted result from mouse studies that although female mice are infertile while on CR, upon leaving a CR diet female mice were still fertile at an age when all non-CR mice were dead.
A genome wide gene expression analysis (microarray) of flies who had been under caloric restriction their entire life versus flies that simply started dieting midway through their life has revealed that there is essentially no change in the gene expression levels between these two treatment groups.