Im really not sure what you could do.
I battle an eating disorder and my boyfriend does know.
He just kinda leaves me alone about it though.
For me, if you were to go behind my back for psychological help, it would make me worse off.
At that point, id feel like a failure and be more depressed than ever.
Its hard to tell you what to do in your sittuation since I dont know the girl.
Just use your best judgement.
Try not to bring it up too much, and definitely dont nag her.
Good luck

Well, you must, firstly, to learn as much as possible about these conditions. But don't judge here hardly, it's something in her hear. Go smoothly - small things can make big differences.

There are a lot of different reasons why a girl will develop an eating disorder ranging from low self-esteem to sexual abuse. It's all very complicated and you have to realize that you alone are not going to make the problem go away. All you can do is be there for her and support her efforts to get better. She is the only one who can fix this.

i also am dating a girl with an eating disorder, i would say the foremost thing you have to do is understand the following:
1.) it's not her fault most likely their was some sort of psychological trigger that set it off and chances are she doesn't know what it is
2.) if she's at a normal bmi chances are she's bulimic i would suggest you check her hands for knicks caused from stomach acid
3.) she sees a disfigured unattractive figure when she looks in the mirror not what you see
i wish you the best of luck it's hard to deal with but worth sticking through

im a girl and i told one of my guy friends about it and he doesnt get it either. What i wish he would understand most is that it isnt a superficial thing, it isnt triggered solely on weight and appearance, its much deeper than that. So for me when he compliments me about my physical appearance it means nothing to me. Therefore takign her to a gym or teaching her about healthy habits probably wont help, its the ambiguous "deeper thing" that is stoping her from eating normally not a lack of knowledge.
As for talking to her about it, its good that you brought it up, I think trying to talk it out and understand her is probably going to be your best option here, because it shows you care. But one thing you have to realise she cant "just stop" its not as simple as that, she may never recover fully.
As for an intervention i would be so angry with you if you did that, she is the only person who can decide that she wants to recover. If you really feel you need to help this way i would research some counselors or help groups in your area and give them to her but just dont pressure her, or you could give her the address to this forum.
You seem like a very caring person the very fact that you are asking for help on this shows you are a good boyfriend, she is lucky to have you.

The other comments are right. I've dealt with bulimia for a long time now and have tried to get help every which way and eating disorders really are not just about 'looking good.' There are TONS of reasons why a person can develop an ED; including a person's genetics. Eating disorders are coping mechanisms.

And also DONT take her to the gym with the intention of giving her a healthy alternitive loose weight. She will most likely take that the WRONG way. In her mind you will be telling her that she's fat and will encourage her ED even more. Instead talk to her about being HEALTHY and nourishing/taking care of her body.

Just try to be supportive. And if you find a good opportunity encourage her to get professional help.