I was ambivalent about the ending but I guessed the author wanted to leave things open to let the readers decide. Ultimately, the problems in beginning were still brutally existent in the end. Is that what she wanted to show us? That some girls (maybe boys too) never get over their disorders and still continue on?
This was similar to Wintergirls but definitely different in many ways. It goes out of the norm to show us that 'perfect' is not existent in humans and that everyone has the hidden flaws, many worse.
Isabella's family is healing and I see progress near the end but they still have a long way to go.