Wow, I'm going to be the only dissenting opinion.
The United States is facing an obesity and cultural problem relating to obesity that is not being corrected. The US attempts to force its children to exercise through its compulsory education system, but it doesnt actually *force* them. Consequently, most people stop after they are required.
The US needs to do one of two things:
1) Start a massive cultural campaign. In Finland they did the exact same thing, to attempt to change the perception that vegetables and fruits were "rabbit food". They reorganised their cities to make exercising more enjoyable and accessable for everyone, and in general had a "cultural revolution". This would require much devotion on the parts of local governments.
2) Make exercise compulsory. Start a system to track the weight of children, and force them to lose weight by modifying their diets at least at school. Force them to exercise more, and make every attempt to stop it within one cycle.
Right now the US is in the middle, almost undecided on the issue and constantly swaying back and forth but not getting anything done. Americans need to decide if they want to correct the problem, and if so then how they wish to go about it.