There are studies going on all the time to try and find an answer. Most probably, if one is found, it will be composed of a series of different reasons.

What has been found is certain common factors that predispose people to suffer from anorexia or bulimia. These factors will not always be present and not necessarily in full.

At the same time, the reverse is true. There are many people who do have these factors in their lives, but do not suffer from an eating disorder.

The following are five groups of factors that have been identified in people with either anorexia or bulimia:

• A traumatic event in the life of the individual.
• A series of events that have caused continuous pain or emotional stress, over a long period of time.
• Abuse, which can be physical, sexual, emotional or verbal.
• Sensitivity to dysfunctional family dynamics.
• Personality features, such as perfectionism, obsessiveness, impulsiveness, low self-esteem, hypersensitivity.

There are certain characteristics that go beyond food and eating and are common to anorexia, bulimia and even binge eating.

Some of these are:

• Low self-esteem, lack of acceptance of oneself
• Hypersensitive to criticism and other standards imposed by culture and society
• Fear of intimacy due to fear of possible rejection
• Perfectionism and complacency from an early age, until the crisis appears
• Unrealistic expectations on oneself and of others
• Extremism, there is no intermediate position
• Addicted to control; aims to control everything around. This is also reflected by observing the family, and many times manipulating others

People suffering from bulimia ingest large quantities of food, but shortly afterwards they self provoke vomiting, or take diuretics or laxatives to avoid gaining weight.

People who suffer from anorexia stop eating, avoid food with high calories and exercise consistently.

People with bulimia usually do not lose as much weight as those with anorexia.

There are also cases of people suffering from both eating disorders, anorexia and bulimia at the same time.

The long term physical effects can also be different.

As that person focuses on food, including calories and weight, she is blocking out or cushioning painful feelings and emotions.

Nobody hurts themselves on purpose. Any conduct that appears to be self hurtful is, from the point of view of that person, the best option she can visualize at that time. The conduct will be the result of what she sees as the best solution. The problem is with the solution that person chooses.

Some people use food as a way of comforting themselves (a sort of security blanket, if you like).

In short eating disorders manifest themselves as problems with food, but that is the tip of the iceberg. The relationship with food is a symptom that camouflages other problems.