calculate how much calories you need
3. Calculate your total calorie needs for weight loss. In order to lose one pound of fat each week, you must have a deficit of 3500 calories over the course of a week. 1  Cutting out about 500 calories each day will result in a 3500 calorie deficit over the course of the entire week. Only aim to lose 1 or 2 pounds per week. 2  If you were to lose weight through diet alone, you'd need a 500-calorie deficit every day to lose one pound in a week. 3  If you were really pushing it and wanted to lose 2 pounds in a week, you'd need a 1000-calorie deficit every day.