If a human achieves the same caloric restriction as a mouse, e.g. 20%, would be we expect the human to have the same health benefits as a mouse? And what about primates?

There is no clear answer to this at this time — that why scientists at the Wisconsin Primate Center are currently studying lifelong calorie restriction (30%) in rhesus macaque monkeys — presumably more pertinent to humans than rats. So far, the monkeys in this study have attained the median lifespan of (unrestricted) monkeys, and the death rate from age-related disorders has only been one-third as high in the restricted monkeys as in the restricted ones. It’s not yet clear how this will equate to increased longevity, but there is already clear evidence that calorie restriction can be tremendously protective in primates.

However, perhaps our best current way to address this problem is to look at Okinawans, a contemporary human experiment in calorie restriction. Studies show that, prior to 1970, Okinawans consumed about 11% fewer calories than would have been considered “weight maintenance” for their lean physiques (averaging BMI 21). By the “BMI 22 reference man” standard, their “true” calorie restriction may have been closer to 12%. But after 1970, the Okinawans were no longer calorie restricted. Yet aging Okinawans now have an average and maximal life expectancy that is about 4-5 years longer than that of current Americans. In rodents, life extension achieved by calorie restriction appears to be more or less proportional to the extent of calorie restriction and the portion of one’s total life spent in calorie restriction. Elderly Okinawans achieved about a 12% calorie restriction for perhaps about half their lives — and now enjoy a 4-5 year advantage in life expectancy. This suggests that humans who managed to achieve a 20% restriction for most of their lives could enjoy a quite substantial increase in life expectancy — provided that this benefit is proportionate in humans as it is in rodents.

← Back to Frequently Asked Questions