One of the most important therapeutic goal in anorexia nervosa is to define with the patient a body weight to obtain. To do so, objective criteria are needed. For this purpose, we studied in a longitudinal way, 9 nutritional parameters in 23 patients with anorexia nervosa, as compared with 23 age - and sex - matched patients with Crohn's disease: body weight, tricep's skinfolds, mid-arm muscle circumferences; serum albumin, prealbumin, transferrin, hemoglobin, cholesterol; urinary creatinine and calcium, magnesium, zinc and copper serum levels and urinary outputs. Despite losses of body weight, of lean body mass and of fatty mass higher in patients with anorexia nervosa than in those with Crohn's disease, the former had higher nutritional protein's serum levels than the latter. These nutritional protein markers were not in anorexia nervosa different from normal values. In anorexia patients, zinc and copper serum levels and urinary outputs were very low. This study suggests that nutritional protein markers of hepatic synthesis are not sensitive markers for malnutrition evaluation and can not be used to follow renutrition efficacy.