Eating or not eating in an obsessed manner has little to do with true hunger. It can be a way to feel in control, to get attention, to punish parents or even to "reward" yourself. Or some people have the impression that weight will influence their popularity. Researchers haven't determined a specific cause for eating disorders, but there are many factors that can help explain how the disease develops.

Coping Strategy
Often, a person suffering from an eating disorder is using the disease as a coping strategy to deal with some other problem, like feeling depressed or guilty. Many people with eating disorders feel like they need to feel fat (even when they are dangerously underweight) so they can keep restricting their food and continue distracting themselves. This can be why denial is often a huge part of eating disorders.

Cry For Help
Sometimes people with eating disorders are blamed for simply wanting attention. But wanting attention is usually a cry for help. Many people suffering from eating disorders don't like reaching out for help or may not even know how to ask for help. Often, the person has become so withdrawn from life that she turns inward, trying to hide her disorder instead of talking to someone about the problem.

Media Influence
Many people with eating disorders have low self-esteem and a negative body image. The media and advertising feed into these insecurities by giving people a false sense of worth. (i.e. "If you lose ten pounds, you will get that dream guy/job/friend/pair of shoes/pet gerbil/whatever.")

The media can also throw off our sense of what's normal. The average woman is not a supermodel, yet pencil-thin models and celebrities are everywhere, from magazines to television to billboards. A person who is insecure may look at these women and try to change themselves to look more like models or celebrities.