If you think that doing sit ups alone will help you get a flat stomach, then you are mistaken. Sit ups don’t target your belly specifically but can help you lose fat in general. Doing sit ups at a moderate intensity for 10 minutes without rest, burns as much as 60 calories. Your weight also has a big role to play. If you weigh less than 68 kilos, you will burn lesser calories in the stipulated time and if you weigh more, you will burn more calories if you do seven sit ups in one minute.