Will Gaining Weight Help With Fat Transfer to the Butt?

Hello dear!!
Thanks for the question and provided information as well. 
Unfortunately, without pictures, it is very difficult to give you a proper answer. 
l recommend you to make an appointment with a board certified plastic surgeon to talk about your goals and anything you need to know.
Good luck :)

It is difficult to evaluate your candidacy for BBL and make recommendations with no photos posted. I would recommend a virtual or an in person consultation for proper evaluation and treatment options. Gaining weight can help with the fat transfer but it is important to remember that fat that has been introduced to the buttocks will act in unison with the rest of the fat in a patient's body and should respond proportionally to any fluctuations in weight that can result from diet and/or exercise. Seek a board certified plastic surgeon who performs many of these procedures, has great reviews and photos, and is an expert in this field.