The diet consists of a relatively low energy intake and contains similar foods to the traditional Okinawan diet. The principal focus of the diet consists of knowing the food energy density of each food item.

The proponents of this diet divide food into four categories based on caloric density. The "featherweight" foods, less than or equal to 0.8 calories per gram (3.3 kJ/g) 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.^[9]