Everyone has their own individual journey to follow. You have chosen the path that is right for you, so you walk your path. Hold your head up high. You've done all you can do. Maybe, just maybe, she'll see you get to goal in a healthy manner and it will inspire her to clean up her act. If not, you can't do anything more to help her. She's grown and she will do what she wants to do.
Good luck to YOU on YOUR journey!!