The above quoted formula is taken as dieting orthodoxy: to lose one pound of fat per week, simply create a 3,500 calorie deficit through diet and exercise et voila, lose a pound a week for as long as you can keep it up. If only it were that simple. Instead, the 3,500 fewer-calories-per-week strategy (what amounts to 500 fewer calories per day) is a good guideline to help create a calorie deficit, but that doesn't mean it will result in one pound lost every seven days.