Tuesday, June 5, 2012

Are You Practicing Hara Hachi Bu?

A few years ago in preparing for a lecture on diet and aging I ran across a study in National Geographic.  In it the researchers analyzed the diet and life style of three different populations where the people not only live longer lives, but longer, healthier lives.  The Italian Sardinia population, the southern Californian Seventh Day Adventist and the citizens from the Japanese island of Okinawa, who all have a large population of healthy centenarians, were part of the study.  So what common factors made these three seemingly unrelated groups connect?  All three reported putting family first (yea!), being physically active every day (good idea), staying socially engaged and eating plenty of fruits, vegetables and whole grains.  Amen to that.
Okinawans have a saying which  summarizes the philosophy underlying their healthy lifestyle - hara hachi bu. I had never heard this phrase and wondered why it is considered to promote health into the golden years.  The translation – eat until you are 80% full.  I grew up in the “clean your plate” era and so was curious about the reasoning behind this supposed wisdom.
Turns out it takes our brain 20 minutes to recognize that your stomach is full.  As a result, if you keep eating until your mind registers you are full; you will have over eaten by about 20%. If we push away the plate and stop eating when we feel we are at 80%, it is likely that your body will get exactly what it needs.  The feeling of complete satiation arrives in about 20 minutes and the risk of overeating is greatly diminished.
Many studies show that individuals or populations that routinely under eat by this subtle percentage not only maintain a better weight, but have more energy.  This makes sense.  When we eat to full capacity our stomachs are slightly overstretched which means that the next meal will require just a bit more to achieve fullness.  Continually adding a few more calories to attain satiation each day results in noticeable weight gain.  And consider that digesting food requires both biochemical and muscular activity from the body. By not continually overtaxing the metabolic system with the need to process more calories than are required, we may reserve our precious energy for things other than processing food.
Okinawans who practice hara hachi bu enjoy more than stable weight and vitality.  Almost 29% of Okinawans live to be 100 years old; which is about four times the average in western countries. They consume about 1,800 to 1,900 calories per day. Their typical body mass index (BMI) is about 18 to 22, compared to a typical BMI of 26 or 27 for adults over 60 in the United States.  And in Okinawa, Heart Disease rates are 80% lower, and stroke rates lower than in the US.  Rates of cancer are 50-80% lower - especially breast, colon, ovarian and prostate cancer. Dementia is rare.  These are impressive statistics.