If you haven't seen this, check it out. I don't have HBO, but luckily they've been showing it on DISH on channel 102. I watched it all while I was out w/ my pain. Might be some stuff in there you help you, but if nothing else it was VERY interesting hearing about the development of the obesity problem and what all plays into it.
One thing I found very neat is the Moblie Market in Nashville, TN. It's a little farmer's market in a traler that they take to neighborhoods that don't have supermarkets (usually low-income inner-cty ones). It gives the residents the opportunity to purchase fresh fruits and veggies at what looked like reasonable prices.