Why BMI is not the ultimate measure of health

Varför BMI inte är den ultimata måttstocken för hälsa

In today's society where health and well-being are at the center, BMI (Body Mass Index) has become a widely used standard for assessing a person's health status. But is BMI really the most reliable and accurate indicator? In this blog post, we'll explore what BMI is, its limitations, and why it's not always the best way to measure health.

What is BMI and how is it calculated?

BMI is a simple mathematical formula used to assess a person's body fat based on their weight and height. The formula is:

BMI = weight (kg) / (height (m))^2

BMI table showing different BMI values and the corresponding categories of health status according to the World Health Organization (WHO):



< 16.0

Severely malnourished

16.0 - 16.9

Moderately malnourished

17.0 - 18.4

Slightly malnourished

18.5 - 24.9

Normal weight

25.0 - 29.9


30.0 - 34.9

Obesity class I

35.0 - 39.9

Obesity class II

≥ 40.0

Obesity class III


BMI gives a number that is then used to place individuals into different categories, such as underweight, normal weight, overweight and obese. This can provide a rough idea of a person's general state of health, but there are several significant limitations with this approach.

What limitations are there with BMI?

  1. No consideration for body composition: BMI does not take into account differences in muscle mass, bone structure or body composition. Two people with the same BMI can have completely different proportions of muscle and fat.
  2. Does not measure fat distribution: BMI does not provide information about where the body fat is located. Research has shown that fat stored around the stomach can be more harmful to health than fat stored elsewhere.
  3. Gender and age are ignored: Age and gender affect body composition and health status. Nevertheless, the same BMI categories are used for all ages and sexes.
  4. Health and lifestyle excluded: BMI does not take into account a person's overall state of health, dietary habits, physical activity or other factors that affect health.
  5. Ethnic and genetic differences: Individuals from different ethnic and genetic backgrounds may have different health risks and body composition, which is not reflected by BMI.

What are the alternative methods of measuring health?

  1. Waist measurement: Measuring waist circumference can provide better insight into fat distribution and risk of diseases such as heart disease and diabetes.
  2. Body composition analyses: Techniques such as DXA (dual-energy X-ray absorptiometry) and BIA (bioelectrical impedance analysis) provide a more detailed picture of body composition, including fat, muscle and bone mass.
  3. Physical condition: Measurement of fitness level, strength and flexibility provides a better understanding of the individual's physical ability and state of health.


Common questions and answers about BMI (Body Mass Index) and alternatives to the BMI measure:

What is BMI?

BMI stands for Body Mass Index and is a numerical indicator used to assess the relationship between weight and height in a person. It's an easy way to get an idea of a person's body fat in relation to their weight and height.

How to calculate BMI?

BMI is calculated by dividing a person's weight (in kilograms) by the square of their height (in meters). The formula is: BMI = weight (kg) / (height (m))^2.

What BMI categories are there?

According to the WHO (World Health Organization) and other health authorities, BMI is divided into different categories: underweight, normal weight, overweight and obesity. These categories are defined based on different ranges of BMI values.

What does BMI say about my health?

BMI gives a general indication of your body fat percentage in relation to your weight and height. It can be used as a rough guideline to judge whether you are at a healthy weight for your height, but it does not provide a comprehensive picture of your health.

What are the limitations of BMI?

BMI has several limitations: it does not take into account muscle mass, body composition or fat distribution. It also does not take into account age, gender or individual differences. Two people with the same BMI can have different health conditions and body shapes.

Is BMI a reliable measure of health?

BMI is a simple and quick measurement, but it is not always the most reliable indicator of health. It can give a general idea of weight in relation to height, but other factors such as lifestyle, diet, physical activity and genetics also play a decisive role in health.

How should I use my BMI value?

Use your BMI as a rough guideline and discuss it with a professional healthcare provider. If your BMI indicates overweight or obesity, it may be a signal that you need to make changes in your lifestyle. On the other hand, a normal weight according to BMI cannot guarantee that you are in good health.

Are there other ways to measure health?

Yes, there are other methods that can provide a more detailed picture of your health. These include measurement of waist circumference, body composition analyzes (such as DXA or BIA) and assessment of physical fitness.

What is DXA?

DXA stands for Dual-Energy X-ray Absorptiometry, and it is a medical imaging technique used to measure bone mineral density and body composition. It is an advanced method used to obtain a more accurate and detailed picture of the body's composition, including the distribution of fat, muscle and bone mass.

How does DXA work:

  1. Double energy: DXA uses two different energy levels of X-rays. By measuring how much of these rays are absorbed by the body's tissues, the system can create detailed images that show the density of bones and soft tissues.
  2. Body Composition: One of the main uses of DXA is to measure body composition, that is, the proportion of fat, muscle and bone in the body. By analyzing the different densities of different tissues, DXA can create a clear picture of how these components are distributed in the body.
  3. Benmineraldensitet: DXA is also used to measure bone mineral density, which gives an idea of bone health and the risk of osteoporosis. By comparing the measurements with reference values, doctors can assess the risk of fractures and make targeted recommendations.

What is BIA?

BIA stands for Bioelectrical Impedance Analysis, and it is a non-invasive method used to measure body composition, i.e. the distribution of the body's various components such as fat, muscle, water and bone mass. BIA utilizes the body's electrical conductivity to assess these components.

How does BIA work?

  1. Electric current: In a BIA measurement, a weak and harmless electrical current is sent through the body using electrodes placed on different parts of the body, usually the feet and hands. This current passes through tissues with different electrical conductivity.
  2. Tissue resistance: Depending on the density and composition of tissues (such as fat, muscle and bone), different tissues will offer different resistances to the electrical current. Fat tissue has higher electrical resistance while muscle tissue has lower resistance.
  3. Calculation of body composition: The BIA system uses the electrical resistance information to calculate the amount of lean mass (muscle, bone, etc.) and body fat. This is done using specific algorithms and equations.

BMI is a simple and easy-to-use measurement, but it is important to understand its limitations. Using BMI as the sole measure of health can lead to incorrect assessments and treatments. To get a more complete picture of one's health status, it is important to use other measures and analyzes that take into account the individual's unique characteristics, lifestyle and genetic factors. Focusing on a holistic view of health and wellness provides a more accurate picture of a person's well-being and helps make better informed decisions for a healthy lifestyle.




Leave a comment

Please note that the comment needs to be reviewed before publication

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.