You know, I don't know if they necessarily diagnose someone as having both Anorexia and Bulimia at the same time, I think they sometimes just lump the bulimia in and call it "Anorexia- Purging type", but either way. I had anorexia and then bulimia(they frequently go hand in hand). As you can see from the responces, eating disorders really mess up your digestive system The people who have them do want to be underweight usually, but the real reasons behind it is that it's a way to cope with things you're unable to deal with. Obviously a bad way to cope though!