Who hasn’t come home and done some sit-ups after an indulgent meal? Unfortunately, doing dozens of sit-up every night isn’t going to give you a flat stomach. The only way to lose fat from your belly is to lose fat from your entire body. While strengthening your abdominal muscles can be beneficial, it will not make you lose the layer of fat that covers them. High-intensity, full body workouts are more effective for fat loss than doing exercises like sit-ups that work just one group of muscles.