Scientists and researchers have no definitive answer about what causes anorexia nervosa, an eating disorder characterized by a strong, sometimes life-threatening, desire to avoid food. Many theories attribute its development to body image issues, while other studies have linked it to depression, obsessive-compulsive disorder and other preexisting psychological conditions. A boy in Britain with an unusual eating disorder may provide some insight both into the cause of the disorder and the treatment.

The boy, who is only two years old, has refused all solid foods and almost all liquids since his birth, though he was physically capable of ingesting food without problems. As a result, his growth and development were stunted and a feeding tube had to be implanted to provide him with sufficient nutrition. Convinced that the problem was psychological, doctors at an Austrian hospital, working with the parents, tried a controversial technique of starving the child into eating. The tube was removed and the boy was surrounded with food, as well as by people who helped encourage him to eat. The theory is that the psychological problem cannot be resolved unless the affected person actively wants to eat.

At first, the boy ate nothing, but during the course of the three-week treatment he made progress. He began with water and progressed to milk, yogurt and finally to solid foods. His delighted parents say that he is now eating progressively more every day.

Is this a treatment that will work for everyone afflicted by anorexia? Probably not, but this case does provide support for the notion that, for at least some people, the problem has a psychological root and that it is not something untreatable.

Can you really have a diet that is too healthy? Yes, there is a point at which the desire to eat healthy turns into a disorder called orthorexia. It has been characterized as a "fixation on righteous eating" and usually develops when people are concerned over quality to the exclusion of all else, possibly to the detriment of their own health. According to California doctor Steven Bratman, many are raw foodists, vegans, fruitarians or have habits so unusual, they is not yet an official name, as in one case Bratman came across where the patient was "committed to eating only yellow foods." Some people may only eat skinless chicken and other completely plain foods, for example, but basically it is manifested as trying to eliminate anything that could be considered "toxic" and people with the problem constantly revise and restrict their diets. It seems to be social wellbeing that suffers the most, as Bratman reported that many orthorexics rarely get out and spend their time being consumed by thoughts of what their next meal will be, sometimes refusing to spend time with others and avoiding restaurants.

In 2004, the University of Rome conducted a study that indicated as many as 6% of people could have the condition in some form, but it is not yet accepted as a disorder in its own right, largely because the milder forms are socially acceptable. But the diet can overlap with anorexia in its more severe forms, where all food is eventually classified as "toxic" by the afflicted patient, so doctors and who are studying it are working to get it recognized so that treatments can be developed to prevent the progression of the disorder.