There is no one best exercise. The best one, in fact, is the one that you will do regularly. Walking, jogging, cycling, treadmill, elliptical, workout discs, they’re all great. You just have to decide which one(s) you will do regularly, with commitment. And also recognize that your dietary choices are a big part of this equation. Eat enough of the right kinds of foods most of the time to be sure that you have the best fuels for your exercise program.