Dr Bob Palmer, consultant psychiatrist at the Leicester General Hospital, says the reasons why people decide to slim may be complex and indicate more than a dissatisfaction with body shape. In his booklet, 'Understanding eating disorders', he explains how people who restrict their food intake can get caught up in a vicious circle in which fear of failure traps them into developing anorexia or bulimia. But the reasons why some people are more susceptible than others is unclear. Family influences seem to play a part, but again their exact role is not known. Both anorexia and bulimia tend to run in families, although the evidence for a genetic link is stronger with anorexia.
Children also learn about eating behaviour and attitudes from their parents.
There is great social pressure to be slim and attractive, although Dr Palmer believes the influence of fashion, advertising and the media is not enough on its own to explain why some women develop eating disorders but most do not. Athletes, models and dancers who need to keep their weight down are particularly prone. Most sufferers have a low self-esteem and many find it difficult to express their emotions. It is a myth, says Dr Palmer, that anorexia is a problem of the so-called upper and middle classes and that those with bulimia are ''striving, upwardly mobile types who live life in the fast lane''. People with eating disorders are often afraid to ask for help or feel they do not want to be helped.