Looking at this discussion at Laura's blogMy answer to her question;are bulimia nervosa and binge eating disorder different diseases is yes and no. They are distinct and different responses to the same crisis, that of trying to alter one's weight or state. The way these conditions tally must provide some insight into the body's reasoning. Bulimia is interesting as it doesn't directly co-incide with any particular distinct stage, it seems to be about the pre-diet stage one;where the body tries to discourage you by leaving your appetite and hunger open- in the overall way it develops, the actual diet itself;stage two- due to the purging/vomitting which can become a low calorie diet by default. It is because of this that it is tied to anorexia but in a way, is the link between all three of the other disorders. The desire to manage weight or responses to life's challenges is the spur for all including bulimia, the body responds to this with the same instincts and urges as binge eating and compulsive eating disorders, the purging is an attempt to thwart this. Probably the naturalness of the vomitting accounts for the instinct to make oneself vomit. What has intrigued me and I've never gotten to the bottom of this, is why so many fat people seem to be phobic about vomitting, to the point where they will bear considerable discomfort to avoid it or find that they cannot. This is not just physical it is overwhelming emotionally as well. I used to thnk this could potentially answer a lot of questions and provide intesting leads. I am aware that this is controversial, especially the linking of anorexia to dieting. I get the feeling that anorexics are not longer quite so aggresively anti this link as they were in the past, but I think they still resist it. The argument used to hang on the fact that doctors used to label anorexia-the slimmer's disease.
I always thought that was a genuinely accurate shortand, but it was felt that it trivialised anorexia, it's funny but in my experience, it's the other way around, this thinking has hopelessly trivialised dieting.