One of the most exhausting things about having an eating disorder is the non-stop racket in your brain. And while some of that chatter is about calories, food, and exercise - a lot of it is how you compare with other people. Is s/he skinnier than I am? She's eating a salad - she must think I'm so fat for eating a sandwich. So-and-so used to spend X hours at the gym - I only spent Y. More than anything, I just wanted my brain to shut up.