[Determination of body feat in treatment of anorexia nervosa]

Bioimpedance analysis was used for weekly assessments of body fat content in 20 adolescents with anorexia nervosa (mean BMI 15.6 kg/m2; mean age, 14 years 5 months) until the desired weight had been achieved, but for a minimum of 12 weeks. As expected, body fat content increased with BMI. Total body fat increased faster than fat-free body mass, the relative increase being 66%, vs 11% for fat-free body mass. However, an expected association between an increase in the percentage of body fat and resumption of menstruation did not occur. As a noninvasive, repeatable procedure including the assessment intraabdominal fatty tissue, determination of total body fat by bioimpedance analysis is suitable for use in longitudinal studies of anorexia nervosa.