The detection process does not need blood test, which takes a very short time. The detection result is more accurate.
Bioelectricity is not the most accurate method, but it is cheap, convenient, non-invasive, repeatable every day and convenient for continuous evaluation.
Fat is not conductive, muscle contains more water and has good conductivity. Therefore, the resistance can be measured by the change of current and voltage between two points. The higher the resistance, the higher the fat content.
Therefore, the main variable is actually the water content in the body, which is basically accurate only when it is measured at a fixed time every day, usually in the afternoon, after non-strenuous exercise and sweating.
Relatively speaking, if the abdominal fat content is high, it is difficult to get an accurate reflection, which needs to be judged by combining other methods.