Taken from Dan Buettner's book, Blue Zones, on research of four areas in the world with the longest-lived individuals:
Kamada Nakazato is a 102-year old woman living on the Motobu Peninsula of Okinawa, an island archipelago 1000 miles southwest of Tokyo. Okinawa was identified by the researchers as one of 4 "blue zones" in the world where people live the longest, healthiest and happiest lives.
During the authors' visit with Kamada, they observed a pattern of eating among people in this area: mostly plant-based foods grown in their gardens, some fish and tofu,lots of green tea and only occasional meat.
"Before each meal she takes a moment to say hara hachi bu, and that keeps her from eating too much... All old folks say it before they eat. It means 'Eat until you are 80 percent full.'"
"Okinawa may be the only human population that purposefully restricts how many calories they eat, and they do it by reminding themselves to eat until they're 80 percent full. That's because it takes about 20 minutes for the stomach to tell the brain it is full. Undereating, as the theory goes, slows down the body's metabolism in a way such that it produces less damaing oxidants - - agents that rust the body from within."
Low caloric intake was a practice that researchers found among centenarians in all four Blue Zones, averaging 1900- 2000 calories per day. Compare this to one typical fast-food meal of a large hamburger, large fries and a large soft drink containing nearly 1500 calories.