Matt Steinglass has a pretty cool post up about how, in the course of a few weeks, he got healthier simply by living in an urban environment. It makes so much sense: urban areas with crowded streets and limited parking naturally favor walking over driving, and with more walking comes healthier living. Judging from appearances it may not look like I do a lot of walking, but I do, and I enjoy it far more than driving. If it were logistically feasible for me not to own a car and use public transportation, even if it meant tacking another 20 to 25 minutes onto my commute, I'd do it in a heartbeat. I hate driving, and avoid it whenever possible, even when not driving is more expensive than driving.
There is one thing that I'm kind of curious about: Matt says he lost 1.5 kilos in 3 weeks time. That's roughly a pound a week, or 5 miles a day, every day. He must have done a lot of walking.