Overall, I agree with, and like your comment, except for this bit. "1. Some is far, far better than none. You need some exercise simply for proper functioning

Overall, I agree with, and like your comment, except for this bit. "1. Some is far, far better than none. You need some exercise simply for proper functioning of your body; and 2. Walking, and exercise in general, is not the primary solution to obesity. According to a calculator, a 200 lb man burns 120 calories by walking 1 mile in 20 minutes. Not a brisk pace at all. A 12oz can of soda has ~140 calories in it." I believe this over-simplifies the situation, and undercuts the advantages of walkable communities. I live pretty close to one. On walks, I often run into friends, people I vaguely know and just wave at, and sometimes random strangers. Walking outside in pleasant weather increases your dopamine levels, and gives you a restful night's sleep. It is easier to do this walking if you see more people around you doing it. Where would you rather go for a walk at night, a nice place with cosy cafés and a moderate bustle of people, or your friends' dreary suburb in the Midwest with no one around? Also, consider the opportunity cost. When going on a walk after dinner, you may be burning a measly 100-200 calories, but you are also not consuming the 500 calories that you would have if you were binging on that large bag of kettle cooked chips while binging on House of Cards. That is a net saving of 700 calories.