I want to lose 20 pounds in 5 weeks, and I'm confused as to how many calories I should be eating. I've started attempting to lose weight, and for the past two weeks I've been eating 1500 calories, and I've been doing exercise, using a stair-stepper, and walking my dog for 30 minutes, and I only lost 1 pound each week. So I used a calorie calculator because I thought I was eating too many calories, and it said I should be eating 1920 calories! I'm so confused! How many calories should a 5'2 teenage girl eat?