Obesity refers to the deviation from normal weight caused by an increase in body mass or an increase in its fat content. If your body mass increases above a certain level, your risk of developing certain diseases increases. In addition, life expectancy decreases and quality of life decreases with increasing body weight. Body Mass Index (BMI) describes the ideal weight for a person's body height.

BMI formula: BMI = (body weight: body length²)

It is calculated by dividing the body weight in kilograms by the square of the body length or by the length of the body raised to the power of two. BMI best matches body fat mass determined by direct measurement. Therefore, BMI is particularly suitable for assessing disease risk.