[Measurement of human body fat by means of gravimetry. Application of Archimedes' principle].

The weighing of the human body under water is an application of Archimedes' law. Fat being lighter than water or than the structures of lean body mass, body fat can be measured by determining the specific gravity of the human body; that is, by underwater weighing. Body fat has been determined in an "ideal" sample of 14 men and 23 women, all aged 20 years. Testing against a reference measure of body fat makes it possible to test the validity of some anthropometric measurements and of some indices of obesity. These indices offer no advantages over anthropometric measurements.