I don’t buy it, putting aside the fact that there are many public transit-heavy countries with obesity problems, the amount of calories you burn from walking is a drop in the bucket, you can wipe out a full day of city walking with a small portion of French fries.

Diet is a way bigger factor in weight control than activity, unless you’re a pro athlete burning thousands of calories a day from exercise because you’re working out nonstop as your job.

You should still walk for general health, but not for weight loss.

EDIT: this report from Time about Japanese food culture rings true.

https://time.com/6974579/japan-food-culture-low-obesity/