quote:In order to measure the percentage of fat in our bodies, researchers developed different methods and tolls. Some use Infrared, X-ray, and others use Underwater weighing, and Skin fold. A relatively new method is the BIA or Bioelectrical Impedance Analysis. BIA measures the resistance of body tissues to the flow of a small, harmless low-level current. Current flows easier through the body tissues that are composed mostly of water, which is over 70% of our body. Bioelectrical impedance measures the strength and speed of the electrical current sent through the body (impedance measure). It then uses this measurement and additional data such as height, weight and gender to calculate the percentage of fat tissues out of the whole body mass.