How does BIA predict percentage body fat?

The prediction of percentage body fat using Bioelectrical Impedance Analysis (BIA) is based on the principle of sending a low electrical current through the body. This method works because different tissues in the body have different resistance to electrical flow. For instance, lean body mass (which includes muscles and organs) conducts electricity better than fat mass due to its higher water content. When the electric current is passed through the body, the resistance (or impedance) encountered is measured, and this data is used to estimate total body water and subsequently calculate body fat percentage.

BIA is favored for its convenience and quick results compared to other methods, as it requires minimal setup and can often be performed in various settings, from clinical environments to fitness centers. Understanding the direct relationship between the resistance encountered and the composition of body tissues is fundamental to how BIA effectively estimates body fat percentage.