Note: To lose one pound per week, you will need to deficit 3500 calories, or 500 calories each day (3500 / 7 days = 500). However, women should not consume less than 1200 calories and men should not consume less than 1600 calories without medical supervision. (Example: your daily calorie needs are 1600, you are a woman and want to lose weight but deficiting 500 calories would put you at 1100 calories; instead use 1200 calories which will allow you to lose slightly less than 1 pound a week).
To gain one pound per week, you will need to consume 500 calories per day more than your daily caloric requirement. (Example: your daily calorie needs are 1400 calories…to gain 1 pound per week, you should consume 1900 calories per day).