Other than smoking cessation, the health benefits of lifestyle changes for middle-aged adults has probably been oversold:
At most, Dr. Kramer said, the effect of changing one's diet or lifestyle might amount to 'a matter of changing probabilities,' slightly improving the odds. But health science is so at odds with the American ethos of self-renewal that it has a hard time being heard. Here, where people believe anything is possible if you really want it, even aging is viewed as a choice.Genetics and experience have determined the health fate of most people by middle-age. Other than smoking cessation, other interventions may have limited benefit. Maybe weight loss and excercise could help, but very few adults can start managing weight or activity effectively so "late" in life. In any case, much of the damage done cannot be reversed.
Smoking cessation, drugs and surgery -- that's the message for the middle-aged.
Now for the young -- there we ought to be focusing on lifestyle changes, particularly exercise. Alas, our public policies and our social behaviors are not helping.