You’re saying that eating disorders don’t have to be stress related, but the three women I know who suffered from Anorexia, all had to (eventually) deal with the stress that their doctors/therapists believed to be the culprit.
One of em didn’t initially connect the disorder to stress, and although with the help of an excellent nutritionist she was able to eat better for a while, she relapsed soon after that. Once she was in therapy for her anxiety she was successful in beating the Anorexia.
It’s also interesting to note that two of these women had OCD as well, which I believe is also caused by anxiety.