Total-body electrical conductivity method for estimating body composition: validation by direct carcass analysis of pigs.

Determination of body composition by measuring total-body electrical conductivity (TOBEC) is based on the principle that body fat and fat-free mass (FFM) differ in electrical properties. In humans, we are able to estimate body composition only by indirect methods, which have been used to validate the TOBEC instrument. Relationships between TOBEC and body composition were examined using direct carcass analysis of 24 pigs differing widely in body weight and composition (48-137 kg and 14-45% fat, respectively). Highly significant correlations (p less than 0.0001) were found between body conductivity and empty-body water (H2O) (r = 0.979), empty-body FFM (r = 0.980), empty-body crude protein (r = 0.962), and empty-body potassium (r = 0.949). Prediction of empty-body H2O or FFM from TOBEC had a SEE of 2.1 or 2.8 kg, respectively. Thus, the TOBEC method can predict body H2O and FFM over a wide range of body weight and fatness.