When Friday rolls around, your mind automatically flips the switch--off from work and off from keeping your diet. Americans consume 400 more calories during that 48-hour period than on the typical weekday, according to a study published in the Journal of Public Policy & Marketing. (Search: How many calories should I consume a day?) But that doesn't mean you're doomed to pack on pounds--with a little work, you can regain control of your weekends. Move more, eat less, and still manage to have some fun along the way with these 11 strategies.