You’ve probably heard more times than you can count that you need to exercise. But do you really know why? For starters, here are seven reasons: 1.Exercise can help you lose weight. This one’s a no-brainer, but there’s a reason exercise is part of most healthy weight loss plans. “Exercise can increase your metabolism, or the amount of fuel your body can use, which will facilitate weight loss,” says Clifford Edberg, RD, a personal trainer and program manager of personal training and nutrition coaching at Life Time Fitness in Chanhassen, Minnesota.