Hara hachi bun me (腹八分目) (also spelledhara hachi bu, and sometimes misspelledhari hachi bu) is aConfucian[1] teaching that instructs people to eat until they are 80 percent full.[2] TheJapanese phrase translates to "Eat until you are eight parts (out of ten) full",[2] or "belly 80 percent full".[3] There is evidence that following this practice leads to a lowerbody mass index and increased longevity, and it might even help to preventdementia in the elderly.[citation needed]
BiochemistClive McCay, a professor atCornell University in the 1930s, reported that significantcalorie restriction prolonged life in laboratory animals.[4][5] Authors Bradley and Craig Wilcox along with Makoto Suzuki believe thathara hachi bun me may act as a form of calorie restriction, and therefore extend thelife expectancy for those who practice this philosophy. They take the case ofOkinawa, whose population rank at the top in terms of life expectancy: they believe thathara hachi bun me assists in keeping the average Okinawan's BMI low, and this is thought to be due to the delay in the stomach stretch receptors that help signalsatiety. The result of not practisinghara hachi bun me is a constant stretching of the stomach which in turn increases the amount of food needed to feel full.[2]
Yoshida Iwase and colleagues have investigated the reasons why some centenarians are able to reach such old ages without signs of dementia, and among other factors, found that following thehara hachi bun me philosophy might contribute to healthier neurological markers for the elderly.[6]
Okinawans are a minority culture who, although part ofJapan, are descendants of theRyukyuan Kingdom and who had influences from mainland China. Okinawa has the world's highest proportion ofcentenarians, at approximately 50 per 100,000 people.[7] They are known to practisehara hachi bun me,[2] and as a result they typically consume about 1,800[3] to 1,900 kilo-calories per day.[8] The typicalbody mass index (BMI) of their elders is about 18 to 22, compared to a typical BMI of 26 or 27 for adults over 60 years of age in theUnited States.[9]
The philosophy ofhara hachi bun me, is also found in other cultures.
From the teachings ofConfucius,[1] philosophies dating back to the 5th century BCE in China, a proverb found inTraditional Chinese Medicine states:"Chīfàn qī fēn bǎo, sān fēn han" (吃飯七分飽、三分寒) or "only eat 7 parts full, and wear 3 parts less.")[10]
The principle of avoidingsurfeit also appears in Islam, dating back to the 7th century CE by the Prophet Muhammad, embodied in the proverb stating: "you should fill one third of the stomach with liquid, another third with food, and leave the rest empty."[10]
In the 1965 bookThree Pillars of Zen, the author quotesHakuun Yasutani in his lecture forzazen beginners advising his students about the bookZazen Yojinki (Precautions to Observe inZazen), written circa 1300, advised them to eat no more than eighty percent of their capacity, reinforced by the proverbhara hachi bun me.[11]
Hara hachi bun me was popularised in the United States by a variety of modern books on diet and longevity.[12][13]