My suggestion would be to find a counselor, administrator and/or doctor or nurse -- and if you're lucky, a patient or two, as well -- who is either currently, or recently past, being treated in an actual eating-disorders center or half-way house in your area, or as near-by as possible. (Or, barring that, someplace with a national reputation).
And if one place turns you away because of privacy issues, try another.
Some places have officials/doctors/patients who are either willing to talk themselves, or are willing to put you in touch with someone who is. Others don't, and will stick to their guns no matter what. It depends on the place's policies, and general level of openness, cooperation and desire to confront/address the problem in whatever way possible (even more public, media-friendly ones, which they see as having the potential to benefit more people than just those currently in treatment. And they're fine with that, even may want and seek it, to some extent.
As previously suggested, you may have to grant some level of anonymity, or, at the very least, agree to have patients call you, and not the other way around. But maybe not, especially if you can get someone already out of treatment (preferably recently) who is no longer an actively in-crisis patient (this is an important factor in the likelihood you would be allowed access).
Also as previously suggested, perhaps you could be put in touch with someone in one of the place's support/follow-up groups or programs.
One thing to check on: The place might even have a group (or other contact format) specifically for athletes with eating disorders, or, another, closely-related condition known as exercise addiction.
The latter is a real diagnosis, with similar problems and personality characteristics common to people with eating disorders, and these people might give you more fodder, or, could potentially lead you to people with the more classic disorders. Maybe one of them will be another local, even.
You might also try to get/find a contact and/or phone number for a well-known, big-time athlete who has struggled with an eating disorder -- there have been a few, particularly among swimmers, divers, gymnasts and runners -- either recently, or in the past. Anything would help, and that would really lend some name recognition and legitimacy to the issue, and your story. And, certainly, they could relate to the local athlete around whom you're centering your story.
And check with the National Eating Disorders Assn. and the National Institute of Mental Health, too. Someone in those organizations would certainly have something to say, and they might give you more leads, direction, and, of course, facts/numbers/trends, too.
Good luck. It's a tough but important and compelling subject, one that, as you can probably tell, is close to my heart.
