Bio-Electrical Impedance (BIE)
Bioelectrical Impedance is a technique using electrical resistance to determine percentages of fat mass and fat free mass. Electrodes pass a painless current through the body; all the while the impedance is being measured, providing the tester with a body density reading, which is converted into a body fat estimation.
BIE has recently become a more widespread method of assessing body fat, thanks to the inclusion of the technology in many household weighing scales. The advantages of this method are the ease of use and the non-invasive nature of the technology. The major disadvantages of the technique are the sensitivity of the human body, and how easily food and fluid intake and storage can affect the results.
Body fat assessment using BIE is most accurate first thing in the morning, before you have had anything to eat or drink.