I agree that there needs to be more activity as part of the solution. Perhaps if people had to exchange community service for benefits there would be less of a problem in this area.
I do know in my family that several of us have benefitted from making concious dietary changes and the biggest one was simply going back to eating real foods. It takes a little bit more time but the effort is worth it.
Which is why you don't see too many really fat Chinese --- and I'm not sure they're more physically active. It's both --- if you're going to lead a sedentary lifestyle, then you can't consume the calories an active person does. If you're going to eat a lot of lard and tortillas then you should be working off the calories. Plus it's the amount --- you can eat smaller portions of the bad stuff.