Dont wait until a week before your wedding to decide you want to lose weight. Weight Watchers recommends a safe rate of weight loss of up to 2 pounds a week. If your goal is to lose 20 pounds, it may take up to 3 months to reach that goal. Use your beautiful wedding gown as motivation to reach your goal. Wedding gowns can always be taken in, even up to a month before the big day so keep on track by dreaming about the dress.