In ten days in Japan I could hardly spot one or two overweight Japanese people. How different from my recent trips to the US where I was amazed by how the majority of Americans are getting fat. As the doctor said, there may be several reasons:

Is it the portions? Everything in Japan is small. Usually a plate would be composed of 6 or 8 different tiny portions of everything. Even barbecue Japanese style includes beef, chicken, pork and lamb but servings are extremely small.

Is it what they eat? Mainly fish and vegetables (most I could not recognize or name). They charge you for bread (and you have to ask for it as a dish, most restaurants offer the choice of rice or bread). For my taste, less salads and fresh fruit that I would like to but not to mention that dessert list is extremely short. Sweet things are given as gifts (and again, small). Much less flour than we are used to. Even their ice cream was ice with color (yes, they also have the creamy green tea version)

Is it the way of cooking? Most of it is either broiled over a hot pan or steamed (or eaten raw). Most food is not deep fried. Think sushi.

Is it ancient medicine? Lots of green and red tea (said to "eat" fat). Lots of seaweed? Lots of soybeans? Exercise? Surprisingly enough, except around the Royal Palace surroundings I did not see so many people running or exercising (a common scene now everyday in Buenos Aires, New York or London). Biking perhaps but it was clear that our obesity problem is not there yet.

I do have to confess that with the massive number of Japanese food restaurants you miss your Old Italian heritage food (be it pizza or pasta). Most of their plates include small portions of noodles but nothing compares to a good spaghetti dish.