BMI has long been used in medicine and nutrition, but the value is increasingly questioned. If we look at obesity then it appears that the body and the composition of which are much more relevant than BMI.
In the early seventies it was found that fat was important for accurate measurement. This could be measured on the basis of a fold of skin or by body density measurements. BMI is calculated by dividing body weight in kilograms by the square of its length in meters (kg / m2).
Recent research is in doubt about the value of BMI. This is mainly because BMI is associated with fat mass in obese people. To date, there is little or no take into account the mass of people of normal weight. For example, it may occur that at a certain score BMI fat mass varies greatly. This is because other variables such as gender or age that are not included in the calculation.
This can be important because for example women have more fat than men. Older people have more body fat than younger people.
In fact, this means that the use of BMI ignores many effects on the body weight of a human. In short, the body weight and the percentage of body fat mass can not be scaled by the same power. The outcome will vary by the individual.
This may also mean that the your score on a BMI chart indicates that you are healthier than you think.