Okinawan Diet (from Wikipedia)

The Okinawa diet is a nutrient-rich, low-calorie diet^[1] from the indigenous people of the Ryūkyū Islands. In addition, a commercially promoted weight-loss diet (which bears the same name) has also been made based on this standard diet of the Islanders.

Indigenous islanders' diet

People from these Japanese islands of Ryūkyū (of which Okinawa is the largest) are reported to have the longest life expectancy in the world. This has in part been attributed to the local diet, but also to other variables such as genetic factors, lifestyle, and environmental factors.

Generally, the traditional diet of the islanders is 20% lower in calories than the Japanese average and contains 300% of the green/yellow vegetables. In addition, the Okinawan diet has only 25% of the sugar and 75% of the cereals of the average Japanese dietary intake.The traditional diet does include a relatively small amount of fish (approximately 1% of caloric intake) and significantly more in the way of soy and other legumes (6% of caloric intake).

The typical Okinawan reaching 110 years of age has had a diet consistently averaging no more than one calorie per gram and has a BMI of 20.4.

Commercial weight loss diet

The diet consists of a relatively low intake of calories and contains similar foods to the traditional Okinawan diet. The principal focus of the diet consists of knowing how many calories per gram each food item contains. They posit that there is a tight correlation between the high proportion of Okinawans over 110 years of age and the relatively low caloric density of their diet.

The proponents of this diet divide food into 4 categories based on caloric density. The "featherweight" foods, less than or equal to .8 calories per gram which one can eat freely without major concern, the "lightweight" foods with a caloric density from 0.8 to 1.5 calories per gram which one should eat in moderation, the "middleweight" foods with a caloric density from 1.5 to 3.0 calories per gram which one should eat only while carefully monitoring portion size and the "heavyweight" foods from 3 to 9 calories per gram which one should eat only sparingly.