The hardware/firmware analysis of the human body composition is based on the predominant conductivity of the muscle mass of the human body in comparison with fat, which is related to the different content of liquid (water and dissolved elements) in these tissue structures.
Tissue resistance to current is directly proportional to the content of fluid in them: highly hydrated tissues (muscle tissue) are active and powerful conductors, while poorly (weakly) hydrated adipose tissue appears as an insulator in this particular case. As a result, the impedance is inversely proportional to the fluid content in the tissues of the human body. High frequency currents pass through the extracellular and intracellular space (liquids, including dissolved solids), making it possible to measure fat-free mass (lean body mass), while lower frequency currents are absorbed in the extracellular space.
This is an unbiased method of analyzing the composition of the human body in a completely safe way and with a high objectivity rate.