I think there's a lot of misconceptions out there not only about what an eating disorder is (ie. you'll always get the "it's just for attention" or "she's not skinny enough" etc.) but also about those people that are suffering, but don't technically "qualify" for a DSM diagnosis of anorexia or bulimia or even binge-eating disorder. There's so much overlap btwn all of them, but for ex. the fact that someone starves and purges but manages to maintain a close to normal weight doesn't mean they're not in need of help or that things are "okay". Or how many people know about bulimirexia? They're just as "valid" as any other ed or problem.
Eating disorders have nothing to do with how somebody looks or weighs. It's all about the psychological effect that food/eating has on that particular individual. My girlfriend battled anorexia for a year and it was terrifying. She'd have panic attacks regarding food and exercise, cry at every meal, etc; yes she was a stick and was completely emaciated, but even more devestating than the physical/health effects it had on her body were the psychological effects. Her fear of food/weight gain/OCD exercise habits completely dominated her life.
Not everyone with ED is skinny; case in point, at the rehab center she went to, many of the other girls were fairly average sized. Just because your not a stick doesn't mean you don't have an eating disorder; it isn't about weight or anything else you can quantify. It's about the psychological effects that the disorder can have on you.