Bingeing
-When you feel empty or alone, you will try to fill that emptiness in order to feel better, to feel whole. As people with eating disorders use food to cope, they may try to fill the void inside with food. They may associate hunger with loneliness or emptiness, and so when they feel alone- they'll eat to feel better. Bingeing is a way of covering the pain, trying to make it go away through food.
Purging
-There is a reason people who make themselves throw up, take laxatives, or overexercise, call their actions 'purging'. They feel cleansed and pure after they do it. Throwing up is a way of getting rid of anything that isn't pure- it may be food, and it also may be a horrible feeling. They purge- and feel they are clean from the inside, clear from whatever made them feel dirty and un-pure.
Starving
-People who starve themselves may feel they are 'taking up space' in the world. They may feel like they do not deserve to take that space, to feel, to breath, to eat. Losing weight can be a persons way to take up less space, or even- an attempt to take up no space what so ever: to disappear. "I just want to waste away into nothingness"- I have heard people who starve themselves use this sentence, and I have used it myself many times. Starving one's self can be a way of, consciously or subconsciously, committing suicide.
This can also be a cry for help: saying, through the body's emaciation what the persong cannot say by words. Many people with eating disorders feel the need to be someone perfect for the rest of the world, and so they do not talk about their pain. In stead, they show their pain- through the changes their bodies go through.