, or hara hachi bunme is a Confucian

Confucianism

Confucianism is a Chinese ethical and philosophical system developed from the teachings of the Chinese philosopher Confucius . Confucianism originated as an "ethical-sociopolitical teaching" during the Spring and Autumn Period, but later developed metaphysical and cosmological elements in the Han...

 teaching that instructs people to eat until they are 80 percent full. Roughly, in English the Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

ese phrase translates to, "Eat until you are eight parts (out of ten) full". or "belly 80 percent full".

Okinawans

As of the early 21st century, Okinawans in Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, through practicing hara hachi bu, are the only human population to have a self-imposed habit of calorie restriction. Almost 29% of Okinawans live to be 100, about four times the average in western countries. They consume about 1,800 to 1,900 calories per day. Their typical body mass index

Body mass index

The body mass index , or Quetelet index, is a heuristic proxy for human body fat based on an individual's weight and height. BMI does not actually measure the percentage of body fat. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing...

 (BMI) is about 18 to 22, compared to a typical BMI of 26 or 27 for adults over 60 in the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

.

While a professor at Cornell University

Cornell University

Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...

 in the 1930s, biochemist Clive McCay

Clive McCay

Clive Maine, McCay was a biochemist, nutritionist, gerontologist, and professor of Animal Husbandry at Cornell University from 1927-1963. His main interest was the influence of nutrition on aging...

 found that significant calorie restriction

Calorie restriction

Caloric restriction , or calorie restriction, is a dietary regimen that restricts calorie intake, where the baseline for the restriction varies, usually being the previous, unrestricted, intake of the subjects...

 prolonged life in laboratory animals. Authors Bradley and Craig Wilcox and Makoto Suzuke believe that hara hachi bu may act as a form of calorie restriction, thus extending practitioners' life expectancy

Life expectancy

Life expectancy is the expected number of years of life remaining at a given age. It is denoted by ex, which means the average number of subsequent years of life for someone now aged x, according to a particular mortality experience...

. They believe hara hachi bu assists in keeping the average Okinawan BMI low due to the delay in stomach stretch receptors indicating satiety

Hunger (motivational state)

Hunger is a sensation experienced when one is required to eat food. In contrast Satiety is the absence of hunger; it is the sensation of feeling full. Appetite is another sensation experienced with eating, however, it differs from hunger; it is the desire to eat food without a physiological need...

results in a constant stretching of the stomach which in turn increases the amount of food needed to feel full.

Hara hachi bu was popularized in the United States by a variety of books on diet and longevity.