Anorexia

Anorexia (Anorexia Nervosa) is an illness suffered by those who have low self  esteem and an overwhelming desire to gain an unhealthy control over life.  Sufferers of anorexia often struggle with both external and internal challenges such as depressio, anxiety, stress and unhappiness.  Research has been able to make a connection between genetics and anorexia, with external environmental factors being the trigger. 
Some signs of anorexia nervosa are hyer-sensitivity to weight and severe distortions in body image.  Persons suffering from anorexia can displaybehaviors such as obsessive exercising, fat gram and calorie counting, restriction of food, and administration of diet pills and laxatives.

Bulimia

Bulimia (Bulimia Nervosa) is also rooted in low self esteem and is an illness that consists of binging and purging.  Generally, sufferers of bulimia will overeat in a realtively short period of time, usually eating enough for two or more people, then purge themselves of the food consumed, often through means of vomitting.  The binging behavior is usually a means by which sufferers will take out frustrations and anger or avoid them alltogether and purging is the way in which they will punish themselves for behavior which they believe is their fault.  Genetic predisposition has been linked to bulimia with environmental factors triggering the disease. 
Some signs of bulemia are frequent purging episodes followed by feelings of guilt and shame, the misuse of laxatives and diuretics, and over-exercising.  

Compulsive Eating

Compulsive Eating (Overeating) is rooted in the same low self esteem problems and is the closest eating disorder to addiction as food is used as an escape or a filler for a void in life.  People suffering from compulsive eating are generally overweight and aware of their abnormal and unhealthy eating habits, but fail to find any comfort in their condition because of the negative stereotypes placed on overweight individuals.  Often compulsive eaters will feel guilty and experience emotions of not being good enough.  Unlike bulemia, compulsive eaters will binge on food when they experience periods of stress, pressure, unhappieness, and anxiety to ease the pain of their emotions.
Signs of compulsive eating are frequent unhealthy and abnormal eating habits, especially in times of high stress and unhappiness.

Over-Exercise

Over-exercise (Compulsive exercising) is classified as an eating disorder even though exercise is generally considered to be very healthy.  Moderate exercise is healthy, but sufficient food and energy is required for exerscise to have a positive effect, and in compulsive exercising, that element is not present, making the exercise more damaging to the individual than helpful.  Compulsive exercisers will exercise beyond what is considered safe and hold a perspective of not being able to eat if they haven't exercised or if they don't know they will be able to exercise.  The activity of exercising for compulsive exercisers is to burn calories and fat from a binge or anything else consumed.
Some indications of compulsive exercising are exercsing by any means possible, including missing school, work, or hiding in the bathroom or bedroom to exercise.  Compulsive excecisers will use excuses of not being able to exercise as to why they cannot eat at any given time.