Today, our daily obligations of work and home keep us tied to our chairs, and if we want exercise, we have to seek it out. In fact, health experts insist that obesity problem is probably caused at least as much by lack of physical activity as by eating too much. Hence, it is important that people need to move around. However, that does not mean that a lap or two around the old high school track will offset a daily dose of donuts. Exercise alone is not very efficient, experts say. They contend that if you just exercise and do not change your diet, you may be able to prevent weight gain or even lose a few pounds for a while.