Effects of Meal and Its Electrolytes on Bioelectrical Impedance
Bioelectrical impedance analysis (BIA) is a simple, reproducible and indirectly validated technique for the assessment of body composition1–3. It is based on the physical principle that the impedance (or conductivity) of a geometrical system is related to the conductor length and configuration, its cross-sectional area, and signal frequency4. Assuming a constant conductor configuration and using a fixed signal, the impedance becomes a function of conductor (body) volume. The conductive pathway is directly related to the water content of the body. Therefore, the conductivity is minimal in the less hydrated fat tissue and far greater in the fat—free body mass which contains virtually all the water and conducting electrolytes. In other words, the BIA is an index of total body water and evidently affected by the alterations in the concentration of conductive electrolytes5.