The principle of this technology can actually be guessed from the name. Simply put, fat and lean meat are distinguished by their different conductivity.
BIA analysis is to put several contact electrodes on the surface of human skin and input a fixed current to get an electrical impedance value. Then use the formula to calculate the body composition of the human body. On the body fat scale we usually use, there are several smooth metal touch plates that we need to step on barefoot or hold with our hands. These metal contact plates are contact electrodes.
Because the final result of BIA analysis is calculated by formula using electrical impedance value, BIA is a "black box" method, and the measured direct result is very simple. Only one resistance impedance value needs to be calculated, and the rest conclusions need to be calculated. These formulas for calculating body composition are all empirical formulas, and there is more than one. There is still a big difference between different formulas.