Body fat percentage

Measurement procedure

The body fat percentage of a person can be determined by various measuring methods. In principle, the body fat percentage can be determined mechanically, electrically, chemically, by radiation or by a volume measurement method. A very simple, but not entirely accurate method of measurement is the mechanical measurement of body fat percentage by means of calipometry.

Here, the thickness of the skin fold at several points of the body is measured with a so-called caliper, which is nothing more than a length measuring device. However, this type of measurement is not suitable for the absolute determination of the body fat percentage, since, among other things, the so-called visceral fat (visceral fat) is not determined and the method is also highly dependent on the examiner. With the body fat scale, which is based on the principle of the so-called bioelectrical impedance analysis, an electrical measuring method is available to determine the body fat percentage.

The body fat determination by means of body scales is carried out by means of electrodes which are installed in such a way that they come into contact with the bare feet. An alternating current is emitted and the various resistances resulting from the different water content of the tissue types are measured. This allows the body fat percentage to be calculated approximately.

However, the measurement is very error-prone and can lead to incorrect values, for example due to a filled bladder. In addition, a chemical measurement of the body fat percentage is possible with the sulphur hexafluoride dilution method, but this plays a subordinate role. A very precise measurement of the body fat percentage is possible with the double X-ray absorptiometry, also called DXA.

This method is based on the use of X-rays. As a disadvantage of this measuring method, the radiation exposure must not remain unmentioned despite the high accuracy, in addition to a duration of about 15 minutes and a price of about 40€. Finally, two volume measurement methods should be mentioned, hydrodensitometry and air displacement plethysmography, which both provide very accurate results and are based on almost the same principle.

In hydrodensitometry, the body fat percentage is determined by means of water displacement. However, this very precise measuring method is very costly and time-consuming. Air displacement plethysmography, on the other hand, allows conclusions to be drawn about body fat percentage due to air displacement.

Here, the density of the body is first determined by determining the mass and volume. The body fat percentage can then be determined from the density determined. The advantages of this examination method include a short examination time and the fact that the method is not dangerous, so that it can also be used for children and elderly people.