We are to take care of our body, and it should not be abused. We must do the best we can. We are to glorify God with what we have been given just as all the animals do. However, we are not to obsess over looks. Do your best, and then forget your looks and show concern for others.
Remember that if your mind is caught up in self-focus, it is enslaved—caught up in your own desires. You are a slave to whatever has mastered you.
If you go to I Corinthians 12, you learn that you are a part of a greater body…the body of Christ. In this body, there are spiritual gifts—one body and many parts. This, the Church, the true body of Saints, is what you need to love and focus on. Notice how you will have no episodes of bingeing or purging if you transfer your concern to the body of Christ.