Sex burns a lot of calories. Thirty minutes of sex can eighty five calories if not more. Although this might not seem a lot, it really adds up. Fort two half hour sessions will burn 3570 calories which is more than enough to lose one pound. When you double up the session, you are going to lose a lot of weight. This is the best mode of exercise. However, it is going to take work from both a psychological and a physical perspective to do it well.