Body Mass Index

The Body Mass Index (BMI)

"When am I too fat and how much overweight do I have?" This question is currently answered by the BMI according to the latest scientific standards. BMI stands for Body Mass Index. A number is calculated from body weight and height and then evaluated. The formula for this is

BMI =	Body weight in kg

	(Height in m)²

Example for 1.75 m height and 70 kg weight:

BMI =	70	= 22.86

	(1.75)²

BMI Calculator

The calculation is not something you can easily do in your head. It is simpler with a BMI calculator. Just enter your weight and height and read your Body Mass Index. You can also adjust the BMI and see what weight you would need for a desired BMI. As a bonus, a 3D computer figure illustrates the calculated Body Mass Index.

Importance of BMI (Body Mass Index) according to WHO

BMI Value	Meaning
under 19	Underweight
19 to 25	Normal weight
25 to 30	Overweight
30 to 35	Obesity (fatness) Grade 1
35 to 40	Obesity (fatness) Grade 2
over 40	Obesity (fatness) Grade 3

Interesting Facts

The formula for BMI comes from the Belgian mathematician Adolphe Quetelet from the 19th century. In medical research, reducing weight status to a single number is very practical, which is why BMI has become established for this purpose.
The calculation of the Body Mass Index is the same for all individuals. There is no distinction made based on age or gender. For children, there are separate assessments - in this case, gender is also taken into account. A table for this can be found here: www.bmi3d.de/kind.html. The assessment of the value according to WHO (World Health Organization) applies to all adults. This is often criticized because, according to many studies, a slightly higher BMI can be healthily sensible with increasing age. The American National Research Council (NRC) already presented a table in 1989, where, for example, a BMI of 24 to 29 is considered normal from the age of 65. However, such a complicated classification makes the use of BMI in medical research more difficult, which is why it is not used. BMI is merely a rough guideline, as it does not take into account stature and gender or the individual composition of body mass from fat and muscle tissue of a person.

Even with a simple calculator, the Body Mass Index can be easily calculated if you know how. Heres the trick:

	Steps:	Example:
1.	Enter weight in kilograms	70
2.	/ (divided by)	/
3.	Enter height in meters	1.75
4.	/ (divided by)	/
5.	Enter height in meters	1.75
6.	=	=
		22.86

Weight and Blood Pressure

Overweight has a significant impact on blood pressure. In about every second patient, blood pressure decreases when weight is lost. A reduction of 5 to 20 mmHg per 10 kg of weight loss can be achieved. Since overweight or even obesity, along with high blood pressure, is one of the four major risk factors (along with smoking and cholesterol) for cardiovascular diseases, it makes double sense to tackle one's own overweight or obesity.

Criticism of BMI

If you only consider BMI without any other criteria, it can also become expensive. Health insurance companies assess your risk of illness based on your BMI. For example, someone who is very athletic may have a high BMI relative to their height, as it is calculated solely from weight and height, but ignores the distribution of muscle, water, and fat in the body.

In an American study, it was also found that about 8 percent of people with a normal BMI still have an unhealthy metabolism.

Sources

By Sabine Croci. This article is medically reviewed. Last updated (02/2024).
Information on the website and within the app cannot replace a consultation with a doctor, but can certainly complement it.

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