Anorexia is defined as an eating disorder characterized by an overwhelming, irrational fear of being fat, compulsive dieting to the point of self starvation and excessive weight loss. In which the sufferer is 80% below the expected average body weight. However bulimic's strive to satisfy a constant craving for food and nearly all patients are within 10% of their normal weight. This eating disorder involves bingeing and purging more than twice a week, which can have serious medical consequences. Most patients suffering from bulimia are in their twenties and are somewhat older than sufferers from anorexia. Bulimia nervosa resembles anorexia in that both disorders are far more common in western societies and occur more often in middle class than working class families.
The medical model considers the possibility of infection, biochemical imbalances and neuroanotmomy dysfunctions as the prime cause of the above eating disorders. They believe that somatic illnesses may act as a contributing factor in bulimia and anorexia nervosa. Park et al studied four women in 1995 all of whom had had glandular fever before the onset of the eating disorder. He argues that the glandular fever may have influenced the functioning of the hypothalamus, resulting in changes in the body's chemical balance.
Holland et al suggested that genetic factors play an important role in the development of eating disorders. In his twin study theory, he studied monozygotic and dizygotic twins suffering from anorexia nervosa. The monozygotic twins are genetically identical whereas the dizygotic twins have the same genes as any siblings. The