Several Car-Free people have commented that they lost weight after ditching the car. It happened to me too. My doctor thinks regular exercise is one of the few things that slows the aging process and helps prevent associated problems. Here is an article that describes how some people think fat people don't just hurt themselves but cause global problems. I don't know, part of the argument is based on calorie consumption. I understand that a fat person uses more calories just in maintaining the fat, but we car free people also burn calories getting about.

http://news.bbc.co.uk/2/hi/health/7404268.stm