There are approximately 3500 calories in a pound of stored body fat. If you create a 3500-calorie deficit through a combination of diet and exercise, you will lose one pound of body weight. (On average 75% of this is fat, 25% lean tissue) If you create a 7000-calorie deficit, you will lose two pounds and so on. The calorie deficit can be achieved either by calorie-restriction alone, or by a combination of fewer calories in (diet) and more calories out (exercise). The combination of diet and exercise is the best method for lasting weight loss. Sustained weight loss is difficult or impossible without increased regular exercise.