How much should a 14 year old girl weigh in pounds?

That would depend on her height and body composition. This is because weight is related to height and body composition rather than age. In addition, as a modifying factor, does she have Diabetes type 1 or type 2 (type 1 can produce weight loss and type 2 can produce weight loss or weight gain). Please feel free to ask the question again and include more details. Alternatively, for more information about weight in relation to height, and to view the height/weight charts for children and teenagers, please see the page link, further down this page, listed under Related Questions.