Bioelectrical Impedance Analysis (BIA)

A method called bioelectrical impedance analysis (BIA) uses the rate at which an electrical current moves through the body to calculate body composition. Adipose tissue (body fat) produces more resistance (impedance) than lean mass, which slows the current's travel. BIA scales use bioelectrical impedance analysis to calculate the body fat percentage.

Due to the higher water content of muscle than fat, electrical currents pass through muscle more easily than through fat. Your body's reaction to electrical currents is automatically entered by the BIA device into an equation that predicts your body composition. There are various BIA devices available, and they range greatly in price, complexity, and accuracy. Most scales measure an estimate of your total fat, muscle, water, and bone in weight and percentage.