but dont some overweight people have a distorted view of themselves, imean i do to an extent mainly in pictures i see something different even perhaps more attractive in the mirror but when pictures are taken i dont regnoize the person in the picture.
Anyone (and it appears many people) can have a distorted view of themselves, its often what we feel rather then what we see in the mirror. The difference is people with eating disorders tend to take action and to the extreme, shutting out others around them to continue their ambitions. Often if someone un-eating-disordered feels fat, they can be talked around it, and realise they have a distorted view of themselves (if it lasts more then a few weeks or months it could be BDD or Body Dismophic Disorder). But they may not have an eating disorder.
The thing with eating disorders is that they are about projecting whats going on inside, to the outside where it can be controlled, so where as it starts off as having a basis in some people: eg they may well be larger then they were last year or in comparison to friends, they may even be over weight, it really takes on a whole new life and becomes the be all and end all. Not only the answer to feeling better about their weight but "if I could just lose weight everything would be great" and thats one of the dangers.
Another part of an eating disordered persons behaviour can be as an attempt to deal with or process past events or even ongoing events which feel out of control. It can leave a person feeling helpless and fearful and food and weight can feel like a welcome relief which combined with all the energy and time they give it, can easily be taken to extremes in an attempt to wipe out or ignore the other problems.
Now many people do this to some extent in their day to day lives, but its when it gets too far, when it becomes a way of life instead of something that helps someone through life that it becomes an issue.
See, in a nutshell, an eating disorder is about being controlled by food and weight and not being able to get out of it. Its when emotions become entangled in weight and body size and actions taken control the rest of a persons life so they have no life left, just weight, food and body size. Instead of normal friendships and relationships, it becomes food and weight and body size. So life feels less important and infact of no real importance at all. It can feel very depressing and lonely which then drives a person to stregnthen the food/weight relationship further which further iscolates themselves.....
I guess its really hard to describe unless your in it, but say your on a diet and you are asked out by a group of friends. Well someone with an eating disorder may go out, but they don't really have any connection with the people around them, its just with the calories (living in fear of) or overeating to the point where they have shut everyone else out and are having a relationship with the food- as if anyone else may not as well be in the room.
Same goes with exercise: it may not even be productive exercise- I've seen a few people in my time at the gym who visit and do pretty much the same workout but many times don't even use the machines properly, maximum level, slow as a snail for example. I'd recon they have a form of exercise dependance, using exercise to deal and process all their emotions. Instead of working through them in real life or with someone else, it becomes "if I can just get this workout done nothing else will matter, it will all be fine". A form of control, an irrational belief, real life shut out.
So in answer to your question! Its not only one thing that goes badly wrong with someone with an eating disorder, its many little things which all contribute to a bigger picture. Not everyone has all of them, I have known people with anorexia who were aware they were too skinny for example, but its when your life shrinks and you become trapped and cannot get out. When you live ruled by the very thing you created to help you and it no longer helps you, it ruins your life yet you cannot let go.