Why japanese people are thin ?

If you go to visit Japan, or are you leaving there, you will see that people are thin because of their transportation style.

The Japanese are thin because they live an active lifestyle. They often commute to work by biking/train/walking or a combination of all three.

To own a car in Japan is expensive due to their environmental so they
must have other means of getting to and from their destinations. Most of people, bicycle or walk 6-9 miles per day just to get back and forth to work.

Also they have lower obesity rates because their diet is made up largely of fish with vegetables and rice, very few people eat fried foods, they eat smaller portions with a much lower fat content. 

For example, Sushi tastes great and leaves you a feeling of energy and light instead of the heavy feeling.

What do you think? you will be thin, if you try Japanese lifestyle?