Working out and dieting can help prevent obesity but you must choose to do this. I believe if everyone worked out and ate even a little bit better the obesity rate would go down considerably and save many lives. I also think most people are lazy and wont bother to change their habits. This is why we are the fattest country.
This is one way, if everyone was on board, to lower the waistline of many people and help get down the obesity rates. It might also help our future generations stay healthier and live longer. This video has some good tips in it.