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Does Calorie Restriction Work in Humans?


Updated December 06, 2007

Calorie restriction (reducing the total number of calories taken in) has long been known to extend life and reduce the risk of age-related diseases in rodents and primates, but evidence in humans has been lacking. The Okinawans, a Japanese group with historically long lives, has often been proposed as evidence that calorie restriction works (because of cultural beliefs and practices about eating less).

Finally, researchers have examined over 6 decades of data on the Okinawans to determine if calorie restriction plays a part in their longevity. Here's what they found:

Calorie Restriction and Okinawan Longevity

Researchers examined data going back six decades on the diet composition, energy (caloric) intake, activity levels, DHEA in blood and linked those to the mortality data on Okinawans. They could then group the Okinawans into data groups based on their caloric intake. What they found was that the calorie restriction (low caloric intake) Okinawans had little weight gain with age, lower mortality risk from age-related diseases and higher DHEA.

Do People Using Calorie Restriction Live Longer?

The researchers also found that the lower calorie group had an extended average and maximum lifespan. They caution that this study has only been done in Okinawans, which is a particular ethnic group, so genetic factors may be at play.

Should I Start Calorie Restriction?

Looking at the stats on obesity for most of the developed world, a majority of people would benefit from taking in fewer calories. If you are at a healthy weight, calorie restriction with proper nutrition is a fairly serious decision. Whether you go this route depends on any health conditions you may have, how willing you are to monitor the nuances of your nutrition and other considerations. Most of us could start by not taking in excess calories and getting to a healthy weight.


Willcox BJ, Willcox DC, Todoriki H, Fujiyoshi A, Yano K, He Q, Curb JD, Suzuki M. Caloric Restriction, the Traditional Okinawan Diet, and Healthy Aging: The Diet of the World's Longest-Lived People and Its Potential Impact on Morbidity and Life Span. Ann N Y Acad Sci. 2007 Nov;1114:434-55.

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