ESTIMATION OF THE CONSTANCY OF DENSITY OF THE FAT-FREE BODY*

Abstract

The in vivo estimation of total body fat has provided useful information, particularly in young healthy males. When current techniques were applied to a heterogeneous group of subjects with apparently normal hydration, but who had varying degrees of physical fitness and obesity and who varied in age, the inherent weakness of our present techniques and some of their basic assumptions became apparent. Such discrepancies are highlighted in subjects with decreased or increased density of the skeleton. While useful for the estimation of change in total body fat, densitometric and volume distribution methods possess the inherent weakness of dependency upon the assumption that the fat-free body in normally hydrated individuals demonstrates a constant density. Fat-free body density varies considerably among normal individuals and to an extreme degree in patients with bone disease.