I am guessing that you might work with at-risk teenagers. If I am wrong, hopefully this response will still be helpful. These girls have enough issues with self esteem and they don't need someone they see everyday reminding them that they don't fit the profile of a perfect body. Reminding them that no one does, won't mean a thing to them.
Have any on them broached you on your weight loss journey? Do they see the changes before and after in your eating habits? exercise?
If they do, then share some of what you have done, to possibly motivate them to make changes in their life, so they don't need surgery later.
Let the parents know that you don't want to sabatage the working relationship you have with their daughters.