Why do a lot of anorexics seem to eat non-nutritiously?

I keep reading a lot of postings from anorexics that say they are eating crackers and other such stuff that in my opinion has a lot of calories and no nutritional value. It perplexes me a bit that anorexics are eating un-nutritionally when they do eat, just seems a bit odd. I also see a lot of posts from anorexics that say they don't even exercise.

Any insight or thoughts on this? I am ednos on the anorexic side, I'm slender and muscular despite my ways, but I keep myself extremely fit and I take vitamins and herbs and eat nutritious foods if and when I do eat, so I think I am healthy enough and think my aging pattern is perfectly fine to above normal, but I can't understand why people starve themselves and then eat non-nutritional food such as crackers while so doing.