Diagnostic issues in eating disorders and obesity.

A thorough understanding of weight related issues is required for the assessment of patients with obesity and eating disorders. Body weight adjusted for height is used for the diagnosis of both anorexia nervosa (AN) and obesity. For AN, the DSM IV A criterion refers to 85 % of expected weight as a guideline, for overweight and obesity BMI cut-offs are commonly used. Because the BMI distribution changes during childhood and adolescence, the 85(th) and 95(th) BMI centiles are used in the USA to classify children as at risk of overweight and obesity, respectively. 85 % of expected weight is approximately equivalent to the 10(th) BMI centile.