How do I deal with an anorexic girlfriend?

I started talking to this girl almost a year ago, and began dating her a couple months after that. The relationship went well, although I noticed some little quirks about her, like calling herself fat when she wasn't (and isn't). She also didn't eat much. The all of the sudden, she dumped me. Out of the blue, with little explanation. Well a couple months go by and we had talked but hadn't seen each other since the breakup. She calls me one night and tells me she's been in a treatment center for you guessed it: anorexia. We started dating again a month after that, and she just recently finished her stay at the treatment center and I'm very proud of her. I'm just kinda worried for her because I never want to see her live her life like how she was living it with anorexia. I've heard that relapse is likely, and I'm looking for some tips on the things I can do to help her out. I love this girl and seeing her relapse would be terrible. Anorexia led to our breakup the first time, I don't want there to be a second.