The fat mass index is the reasonable parameter for assessing obesity.

in progress The WHO, the World Health Organization, defines obesity as “an abnormal or excessive accumulation of fat that can lead to adverse health effects”. The WHO only determines the degree of obesity using body weight and height in the form of the BMI (body mass index), in which body weight is divided by height² (m²). The value obtained in this way is independent of the most important factor influencing weight, namely height, and thus provides a good basis for comparison between people of different sizes. Although body weight shows a highly significant correlation with a person’s fat mass, the deviations from the correlation can be serious in individual cases. For this reason, BMI is by no means a suitable parameter for assessing whether a person is obese or not. A high body weight – in addition to an increase in body fat – can certainly be the result of strongly developed muscles. Those affected may then have a BMI of significantly > 25 , but by no means too much fatty tissue. Not only bodybuilders fall into this group, but also very muscular athletes are often classified as obese when using the BMI. Conversely, there are an increasing number of people who have a normal BMI but visibly have too much fatty tissue. Nowadays, there are quite affordable and hardly stressful ways to measure the body’s fat mass quite reliably. The DEXA method is considered the gold standard. The bioelectrical impedance analysis, which is often derived from it, is used most frequently. For the problems with these methods, see DEXA and BIA. But if it is so easy to measure a person’s fat mass, then this parameter should also be used to classify the degree of obesity. The indication of fat content as a percentage of body weight is discredited by the fact that muscle mass has a very significant influence on the calculated value for the same fat mass. (always the problems with percentages!) As with the BMI, the influence of body size on fat mass can be practically eliminated by dividing fat mass by body size² (m²). This produces the FMI, the fat mass index, which has a close, highly significant correlation with the BMI. The intersections of the degrees of correlation between the BMI and FMI target values result in the target values for the FMI or the FMI threshold values for the various degrees of obesity. With this procedure, experience with the BMI threshold values can be used and at the same time people who have a fat mass that is too high or too low for the respective BMI can be assigned to the correct degree of obesity. You are welcome to download a table for women or men in which the target values or obesity limits for fat mass can be read for the respective body size. With the help of the FMI, the fat mass can be satisfied for the definition of obesity by the WHO.