What method of body composition testing relies on the premise that different tissues and substances within the body have different resistance to electrical current?

Bioelectrical impedance analysis (BIA) is a method of body composition testing that is based on the principle that various tissues in the body conduct electricity differently. When a small electrical current is passed through the body, fat tissue, water, and muscle offer different levels of resistance. Since fat has a lower water content and, therefore, a higher impedance compared to lean tissue, BIA can estimate body fat percentage and overall body composition. This technique is often favored for its non-invasive nature and relative convenience compared to more complex methods.

In contrast, dual-energy X-ray absorptiometry (DEXA) uses X-ray technology to measure bone density and body composition but does not rely on electrical resistance. Skinfold measurement involves using calipers to gauge the thickness of skinfolds at various body sites, which estimates body fat based on subcutaneous fat deposits. Hydrostatic weighing determines body composition by measuring body density through water displacement, a method that is based on buoyancy rather than electrical resistance. Thus, bioelectrical impedance analysis is the most accurate choice regarding the measurement of body composition through electrical current resistance.