Objective: The weight percentage of body fat in anorexic adolescents on the basis of four distinct formulas (Siri; Lohman; Westrate and Deurenberg; Heyward and Stolarczyk) is compared.
Method: The body composition of 238 anorexia nervosa (AN) patients, divided into four age categories (13-15, 15-17, 17-19, and 19-22 years), was measured by means of densitometry (underwater weighing).
Results: Depending on the formula, the results calculated by the formulas differ significantly in each age category. The Siri formula generally results in the highest mean fat percentage (12.76%-13.39%) whereas the Heyward and Stolarczyck formula shows the lowest figures (8.77%-9.31%). Applying the Lohman and the Heyward and Stolarczyck formulas to the 19-22 years category, results in negative fat percentages.
Conclusion: A clinically useful formula is important for the estimation of body composition in specific age categories. We recommend with some restrictions, to apply the Siri formula in AN patients.