The problem is twofold in America: first and foremost, no one wants to hear that they need to lose weight and exercise more, they just want a quick fix. Second problem is that there's so much profit motive involved that companies are eager to hype the quick fix, especially in terms of pills that doctors can prescribe in a fifteen minute office visit after plugging your numbers into a company sponsored calculator.

Exercise moderately and eat healthier are probably the most important "preventive" means of health care. Even for conditions that aren't directly related to being overweight or lacking exercise, it can help immensely to correct those two issues.