Although many people would like to know "the real prevalance of eating disorders," definative statements are unwarrented. The research is beset by problems with sampling, methods of assessment, definitions of key concepts such as "case" and "binge," and the fact that eating disorders are probably underreported, due to their connection with secretiveness and shame. the following statistics, drawn from the sources at the end of the list, shoulld be seen as general estimates and not fixed truths. The figures are "point prevalences," i.e., they refer to the percent frequency for a given point or period in time.
Bulimia Nervosa (defined strictly in terms of frequent binge-eating and purging via use of self-induced vomiting and /or laxative)
ANOREXIA NERVOSA
ATYPICAL EATING DISORDERS (defined as sets of signs and symptoms which are not extensive or severe enough to meet all the criteria for the "full symdromes" of Anorexia nervosa or Bulimia Nervosa)
IN GENERAL
Combining these figures, and keeping in mind and the limits imposed by methodology, a conservative estimate of the percentage of postpubertal females affected by eating disorders which cause significant misery and disruption in their lives is 5 - 10% (e.g., .5% anorexia nervosa + 2% bulimia nervosa + 4% atypical eating disorder.