On the Japanese island of Okinawa, people have the highest life expectancy in the world. The number of inhabitants over the age of 100 years is three times higher than that in the United States.
Men are expected to live to about 84, while women are expected to live to almost age 90. They suffer only a fraction of diseases that kill Americans: a fifth the rate of cardiovascular disease, a fifth the rate of breast and prostate cancer, and less than half the rate of dementia seen among similarly aged Americans.
Naturally, researchers have wondered why that is. According to Dr. Brian Wansink, American professor in the fields of marketing and consumer research, this comes down to an ancient Confucian practice called hara hachi bu, or eat until you are 80% full. By keeping to this practice, Okinawans eat only about 1,800 calories/day. The result is that their rates of cancer, dementia, and heart disease are much lower than those in the Western World.
Over time, small practices done regularly create significant cumulative results. Hara hachi bu, my friends.