The amount of junk in the average American's diet will eventually cause some type of illness no matter how much exercise one does nor no matter how fast that persons metabolism is. The standard American diet with its emphasis on heavy consumtion of animal product [the average American consumes %40 of his calories from same] and heavy use of processed foods [%40+ of total calories] and little consumption of fresh fruits and vegetables [less than %5 of total calories] is likely to lead to CAD, cancer, diabeties autoimmune disease etc. So not being overweight is not necessarily a sign of good health.

Ive spent good money on a Doctor who specializes in nutritional medicine, he is convinced that we are the richest fatest sickess country in history with the biggest budget for medical care. he claims medical costs went up %40 per cent in the the last 10 years yet heart disease cancer diabetes have all gone up too. Were like a nation of sick kings who have eaten all the rich food while sitting on their backsides. . He claims diet comes first followed by robust varied, exercise .