The Body Mass Index (BMI)

Would you like to know if you’re overweight or of normal weight?  Then simply calculate your Body Mass Index.

The measuring of an adult’s weight is based on the Body Mass Index (BMI).  It is calculated by dividing body weight by height in square metres (kg:m²), and should give an indication as to whether a person is overweight.

Calculate your BMI

·  under 17.5: severely underweight,
·  under 18.5: underweight,
·  between 18.5 und 25: normal,
·  between 25 und 30: overweight,
·  between 30 und 35: obese Grade I,
·  between 35 und 40: obese Grade II,
·  over 40: severely obese, Grade III.

It must be borne in mind that the BMI is only an approximate gauge.  It is possible for people with a strong stature or a large muscle mass (e.g. body builders) to have a BMI of over 25, without necessarily being overweight.  In such cases, measuring body fat can be helpful, as BMI can’t differentiate between fat and muscle mass, as it only takes body weight into consideration.  BMI doesn’t necessarily fit especially short or tall people either.  You can find out more about body fat content here.  You can determine your person body fat content with the Body Fat Analyzer.

When calculating BMI, age must also be taken into consideration.  The following age-related standard BMI values are valid:

For children, there are special values, and you should therefore always seek medical advice from a paediatrican.

As well as age, gender also plays an important role.  As a general rule, men have more muscle mass as a proportion of their total body weight than women.  Therefore, the upper and lower limits of BMI classification are a little higher than for women; according to the Federal Centre for Health Education, normal weight falls into a range of 20 to 25, while for women, it falls between 19 ad 24. 

Incidentally, the BMI was not developed for healthcare policy.  It was initiated by American life assurance companies, with the aim of developing a simple classification for the calculation of life assurance premiums, as the risks of being overweight are especially relevant in the USA (due to the continual increase in the overweight population).

On its own, BMI can’t tell you anything about the risk of heart or circulatory disease as a result of being overweight.  The degree of overweight is of less significance than the pattern of fat distribution as a risk to the cardiovascular system: especially detrimental are fat deposits around the waist and surrounding the internal organs.  This internal fat, known as intra-abdominal fat or visceral fat, has a strong influence on the metabolism.  It influences lipometabolism and carbohydrate metabolism (sugar metabolism), and can result in lipometabolic disorders, as well as diabetes.