Sadly, I think the only way for most Americans to maintain a healthy lifestyle would require significant, paternalistic education and intervention. One idea others have proposed would be clearly-and-emphatically warn of future denial of certain healthcare expenses and conditions for people that fail to achieve and maintain reasonable goals to curtail high-risk lifestyle choices, i.e., smoking, poor diet. The key is conditions which arise even with good lifestyle habits should have priority over people that don't take care of themselves and expect everyone else to clean up their mess.

(I'd be first in line because I could lose 20 lbs (9 kg).)