- Whole-body dual photon measurements of body composition were made in 9 controls, 15 athletes and 5 patients with eating disorders. Measurements of lean body mass, mineral mass and fat mass were accurate. Lean body mass and fat mass were measured with reliabilities of about 0.8 kg while for total body bone mineral mass, the reliability was about 60 g. Women had a smaller lean body mass and a greater fat mass than men. Women with eating disorders had the same body composition as males. Measurements of body composition by dual photon absorptiometry are safe and reliable.