I can’t decide whether I’m heartbroken or relieved by the results of the latest study on calorie restriction and longevity in monkeys. In contrast to a study published in 2009, which found that calorie restriction extended the lives of monkeys, the new study failed to find a survival edge for low calorie diets:
The verdict, from a 25-year study in rhesus monkeys fed 30% less than control animals, represents another setback for the notion that a simple, diet-triggered switch can slow ageing. Instead, the findings, published this week in Nature1, suggest that genetics and dietary composition matter more for longevity than a simple calorie count. [Nature News]
The 2009 study found that 13% of the low cal group died of age-related causes compared to 37% of the control group that ate a normal diet.
Some humans went out and put themselves on calorie restricted diets after reading about the purported life extension benefits of CR for monkeys and rodents.
Let this be an object lesson: No one study is ever definitive – not the 2009 study and not this one. Scientists will be going back over the results of the new study to try to explain the discrepancy.
Some experts hypothesize that the monkeys in the new study missed out on the life extension benefits because they were fed a high protein, low calorie diet.
Others wonder if the stress of the experiment erased the survival edge of calorie restriction. The monkeys are housed alone in small cages so that their intake can be precisely monitored.
I guess we should be grateful that the study didn’t find that starvation and solitary confinement dramatically extend lifespans. How depressing would that be?
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