Health and Wellness

This Japanese 80% diet rule can help you live a longer life, says longevity researcher

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If you want to live to a healthy 100, eat like healthy people who've lived to 100.

One place to look is Okinawa, Japan, one of the world's Blue Zones — or exceptional hot spots where people live extraordinarily long, healthy and happy lives. For every 100,000 inhabitants, Okinawa has 68 centenarians — more than three times the numbers found in U.S. populations of the same size.

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Eating with mindfulness, intention and awareness is one significant characteristic that has been proven to aid in longevity rates among Okinawans.

'Hara hachi bu': Everything in moderation

If you've ever been lucky enough to eat with an Okinawan elder, you've invariably heard them intone a Confucian-inspired phrase before beginning the meal: "Hara hachi bu" — a reminder to stop eating when their stomachs are 80% full.

Research shows it takes roughly 15 to 20 minutes for your brain to register that your stomach has reached capacity. And eating slowly, by practicing hara hachi bu, helps short-circuit this.

In other words, if you stop eating when you think you're 80% full, you're likely actually 100% full (you just don't know it yet).

How Americans can benefit from this practice

Again and again, scientists and researchers have found that one of the biggest problems with the typical American diet is that we eat too much.

According to a study from the Pew Research Center, Americans are consuming far more calories each day than is recommended (estimates from the U.S. Department of Health and Human Services range from 1,600 to 2,400 calories per day for adult women, and 2,000 to 3,000 calories per day for adult men). 

In 2017, the average American consumed more than 3,600 calories daily, a 24% increase from 1961, when the average was just 2,880 calories, the study found.

Dr. Brian Wansink, author of "Mindless Eating," spends much of time researching food habits around the world. "There's a significant calorie gap between when an American says, 'I'm full,' and when an Okinawan says, 'I'm no longer hungry,'" he tells me. "We gain weight insidiously, either by stuffing ourselves or by eating a little bit too much each day mindlessly."

What you eat matters, too

Older Okinawans adopt a plant-based diet, with their meals mostly consisting of stir-fried beans, spinach, mustard greens, sweet potatoes and tofu all of which are high in nutrients.

Goya is another popular staple. Also known as "bitter melon," goya is rich in antioxidants, vitamins and minerals that can lower blood sugar levels and improve immune system health to help fight against viruses.

Although Okinawans do eat pork, fish and other meats, these are typically a small component of their overall consumption.

Putting 'hara hachi bu' into practice

Simple changes in everyday eating habits can help put the secret of hara hachi bu into practice for improved health.

Here are four easy steps to get you started:

  • Don't obsess over calorie intake or weight loss. The Okinawan way is to do all things in moderation. As you eat, practice mindfulness by listening to your body.
  • Eat slowly. Eating faster results in eating more. Slow down to allow your body to respond to cues, which tell us we are no longer hungry.
  • Focus on food. Turn off the TV and keep all other forms of digital devices away from your eating environment. You'll be less distracted, consume less and savor the food more.
  • Use small vessels. Choose to eat on smaller plates and use tall, narrow glasses. You're likely to eat significantly less without even thinking about it.

Dan Buettner is a longevity researcher, National Geographic Fellow and author of "The Blue Zones: Lessons for Living Longer from the People Who've Lived the Longest." His latest bestseller, "The Blue Zones Kitchen: 100 Recipes for Living to 100," fuses scientific reporting, National Geographic photography and recipes that can help you live to 100.

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