"Washoku" traditional Japanese food is added to the Intangible Cultural Heritage list by the United Nation's cultural organisation Unesco. Japan has the highest life expectancy and it is connected to their diet.
There is a style for Japanese meal. It is called " ichijyu sansai" 1 soup, 3 dishes. ( 1main and 2 side dishes) plus rice. you can take carbohydrate with rice, water from soup, protein and other vitamins and minerals from side dishes. As you ca see, traditional Japanese meal style is well balanced in nutrition wise.
(Photo credit: All about Japan.com)
Low fat- With this style, whole meal is about under 600- 700 kcal. Also, eating lots of grainscereals and fish means there aren't many chance of taking fat. Butter and oil is often not used in Japanese cooking.
Umami- Umami is another thing about Japanese meal, as we use dashi and yakumi (natural condiment), not so many condiments needs to be used. One thing you might worry is salt in Japanese food. As soy sauce is used in quite a lot of meals, need to be careful taking too much salt but less salted soy sauces are sold in the supermarket these days.
fermented food- such as miso, natto, they keep your immune system good to help you being healthy. they work for intestinal function, they keep you healthy from inside of body.
A key of being healthy eating Japanese food is nutrition balance.