answered question 7/21/2010 If A 15 Year Old Girl Who Is 5.2 Has 800 Calories A Day Is This To Little Or To Much? How Many Calories Should A Teen Girl Eat Each Day To Loose 1.5 Pounds A Week? Please Only Answer If You Realy Know What Your Talking About I think that you're eating too little, you could probably bring it up to 900, and into the thousands if you exercise. But I do recommend bringing it up a little more.