Hi,

I can't rec many specific Dean eating disorder fics (I go for Sam myself), but there is this one:
http://archiveofourown.org/works/1530608/chapters/3238505 which features bulimic Dean. Its Destiel, and also features Sam and some Bobby too.

There is many more on AO3, if you want to just sift through, and hopefully there will be some in there that you will like :)
http://archiveofourown.org/works?utf8=%E2%9C%93&work_search%5Bsort_column%5D=revised_at&work_search%5Bfandom_ids%5D%5B%5D=27&work_search%5Bcharacter_ids%5D%5B%5D=26&work_search%5Bother_tag_names%5D=&work_search%5Bquery%5D=&work_search%5Blanguage_id%5D=&work_search%5Bcomplete%5D=0&commit=Sort+and+Filter&tag_id=Eating+Disorders

Hopefully that is somewhat useful, sorry to not be more help. Also I'm not sure how to link things properly, so sorry bout the long links.
Good luck :)