What does a BMI tell us

How meaningful is the BMI?

Am I too fat, too thin, or just right? The answer to this question is the one Body mass index (BMI). It is considered THE measure when it comes to assessing our body weight. But the meaningfulness of the body mass index has its limits. You can find out which ones are in our blog post today.

What does the BMI say?

The body mass index results from the Body weight to height ratio. It is calculated by dividing the weight (in kilograms) by the size (in meters) squared.

BMI = body weight / height2

According to the classification of the World Health Organization (WHO), anyone who has a BMI between 18.5 kg / m² and 25 kg / m²Has.


Why should I care what my BMI is?

Numerous studies suggest that being overweight with one higher risk of cardiovascular disease connected is. These are the number one cause of death in Germany. The body mass index allows conclusions to be drawn about the cardiovascular risk (cardiovascular = heart and blood vessels). These conclusions are based on epidemiological data. But people do not always fit into this grid and a BMI in the ideal range does not automatically mean the best possible health. Exercise, nutrition, relaxation, stress and genes: that Body weight is just one of many factorsaffecting cardiovascular risk.

Flegal et al. In their sensational 2013 study, they even came to the conclusion that overweight people (BMI = 25-30) live longer than people of normal weight. However, most experts agree that one Body mass index in the normal range is associated with the lowest risk of disease. A study of 190,000 Americans published in 2018 confirms this again. According to the results, people of normal weight do not live longer than overweight people (BMI = 25-30), but they develop cardiovascular diseases at a later point in time. Strokes, heart attacks and heart failure were also significantly more common in overweight people. Obesity (BMI> 30) increases the risk of cardiovascular diseases even more and life expectancy is reduced in this group.

What does the BMI not take into account?

The body mass index is a measure to assess the nutritional status. Simple and straightforward to use and widely used. But it has its limits. Individual factors such as age, gender or muscle mass are not taken into account. This means that the BMI has little informative value for some people. A big point of criticism:The BMI only takes into account body weight, not body composition. Whether the weight comes from muscles or fat makes no difference on the scales, but it does make a difference to your health. Because especially the fat deposits on the stomach are considered particularly harmful. A couch potato with a big belly can have the same body mass index as a well-trained athlete, but have a completely different fat and muscle distribution.

You read why belly fat is so dangerous here.

What alternatives to the BMI are there?

One achieves clearer results Body Composition Analysis. This provides information about the percentage of fat and muscle in the body. You can determine the body composition, for example, through Skin fold measurement with caliper pliers or Bioelectrical impedance analysis (BIA). In addition to the percentage of fat, the Fat distribution an important role. A simple way to keep an eye on them is to measure with a tape measure. Ideal would be a Waist circumferenceless than 94 cm for men and less than 80 cm for women. In addition, the Waist-to-hip ratio (Waist-To-Hip Ratio, WHR) are used. The values ​​here are ideally below 0.85 for women and below 1 for men.

WHR = waist circumference (in cm) / hip circumference (in cm)


The body mass index has its limits and is only used as a Guideline and quick assessment. In addition to weight, the harmful belly fat should also be kept in mind. If you also have regular blood pressure and blood lipid checks, you will further reduce your cardiovascular risk.



Tags: BMI, body weight, body height, body mass index, overweight, underweight, normal weight, obesity, bioelectrical impedance analysis, fat distribution