According to this LA Times article, citing the Archives of Internal Medicine, it takes just four lifestyle changes to decrease your risk of stroke, cancer, diabetes, and coronary artery disease by 80%. These four factors are: avoid smoking, avoid obesity, moderate exercise, and eating a healthy diet. Well duh. We physicians have been preaching this concept for decades. But decades of research into the benefits of diet and exercise hasn't really changed anybody's mind. In all the health care debates, America's higher mortality rate compared to other industrialized nations is repeatedly brought up, as if insuring more people and spending more money will make a big difference.
The article also states that even if you accomplish two of the four factors, avoid obesity and smoking, your risk of getting a chronic disease decreases by 72%. So I guess I'm doing pretty okay. Can I also add attempt to eat healthy? Will an occasional Big Mac worsen my risk improvement to 65%? I promise I'll do better at the exercise part but 72% is already pretty darn good and I'll have more time to spend with my kids instead of being at the gym.
Nowhere are the genes you inherit mentioned as a risk factor. We've all heard of the 45 year old marathon runner who collapses from a sudden MI. Or the college sports player who has sudden death from a cardiac arrhythmia. George Burns lived to be over 100 years old while smoking a cigar. So this has not been taken into account. Since you can't choose your parents, you might as well do what your doctors tell you and diet and exercise, as always.