Technically, a pound is 3500 calories. So for every 3500 calories you burn, you should lose a pound. To use this information correctly, you need to figure out how many calories you are eating per day to maintain your weight. If it takes 2200 calories a day to maintain your weight, and you start eating 1500 calories a day, that's already a deficit of 700 calories. If you burn another 350 calories through exercise, then you have a deficit of 1050 calories which means you could lose a pound in 3.3 days or 3 pounds in about 10 days.