80 Percent Full
One of the most unique parts of the Okinawan diet is the idea that you should always eat until you are about 80 percent full. This idea of not over indulging is at the core of the traditional Okinawan diet. There is however little scientific research to link the concept of never being completely full to living longer (one of the biggest benefits of the Okinawan diet).
The idea that a low calorie diet will help you live longer has been under investigation by scientists for the last 25 years. A study has been underway that kept Rhesus monkeys, an evolutionary cousin of humans, underfed and at a weight equivalent to a six foot tall man weighing 125 pounds. The idea was that by restricting their caloric intake, the monkeys would live longer.
What the results showed was that while monkeys who were underfed were less susceptible to cancer, they did not live any longer than monkeys who ate a full diet.
This is not an argument for over eating! There is hundreds of studies that show that when you eat more food than your body can effectively use, you will gain weight and health problems. While there is a correlation between Okinawans eating less than most people around the world and living longer, what I think is important is that this study suggests that the real cause of the Okinawan’s extended lifespan lie in something other than their low-calorie diet. It may very well be the large amount of sweet potatoes or even the high amount of Omega-3 fatty acids, but it is very unlikely that the low calorie part plays a role in it.
Lifelong Friends and Activity
One of the other unique aspects of Okinawan lifestyle is the idea of lifelong friends and no concept of retirement. Many Okinawans including Gichin Funakoshi and Shoshin Nagamine worked their entire lifetime and never felt that age was a limiting factor in what they could do. Funakoshi famously would wear his iron clogs to help train his muscles well into the end of his life. Equate that to your 90 year old grandpa going to the gym once a day or going on a 3 mile walk daily.
The other aspect is having lifelong friends. In a place of small villages and limited population, many of the people in Okinawa who live to be 100 have grown up around the same group of friends and continue to bond with them a century later. This is something that I speculate aids many aging karate instructors who have a large base of students. People with common interests that you can regularly talk with and have an engaging conversation that stimulates the mind (and body in the case of karate).
While it looks like starving ourselves is not the key to living longer, I think keeping in contact with my friends and embracing a dojo as a second home with a second family, rather than just somewhere I workout, may be the keys to living longer. Anyone with family members who lived past 90 have any thoughts on what helped keep them going well into old age?