BMI

Geschatte leestijd: 7 minuten The BMI, abbreviation for Body Mass Index, indicates whether your body weight and height are in a healthy proportion with each other. Another name for the BMI is the Quetelet Index, abbreviated QI. The BMI is a quick and simple indication of whether your weight matches your height. However, it is not the case that BMI is a good method for measuring whether someone is actually healthy, as it does not take into account factors such as age, amount of muscle mass, and amount of fat mass. If your existing muscle mass is higher than average, this can result in a high BMI, but that doesn’t mean you’re unhealthy. In this article, we will tell you a little more about the history and creator of the Body Mass Index and where you can apply the BMI. Additionally, we have a BMI calculator so you can quickly calculate your own BMI.

What does BMI stand for?

One of the best-known terms for expressing weight in relation to height is the Body Mass Index, better known as BMI. It is an index in which body weight is expressed in relation to body height. The calculation is quite simple and therefore it is also often used: Divide the body weight in kilograms by the body height in meters and divide that result by the height again. The indication that this index then provides is an estimate of whether you are at risk of health risks. Roughly, the BMI indicates the amount of body weight. A common mistake is that the Body Mass Index stands for body fat percentage, which is certainly not the case. BMI does not reflect your body fat percentage. The Body Mass Index is also called the Quetelet index (abbreviated QI).

History of the Body Mass Index

The Body Mass Index was originally conceived by the Belgian Adolphe Quetelet in the 19th century. Quetelet was originally a mathematician and astronomer but had an above-average interest in statistics with a social character. For example, he kept track of how many people died monthly in Brussels and had thoughts about what the average person would look like. Based on the latter thought, he started with his Quetelet Index, a quick indication of whether someone is too thin or too fat based on height and weight. It was only later, in 1972, that the QI index was renamed the popular BMI index.

Meaning of the Body Mass Index

The meaning of the Body Mass Index is limited because it only takes into account 2 variables: height and weight. The importance of calculating the Body Mass Index stems from the fact that people were becoming increasingly overweight at the end of the 20th century. Based on a quick BMI calculation, it could be determined whether someone was too thin or too fat for their height. A high BMI can lead to health risks. The outcomes of the BMI can be divided into the following categories:

Less than 18.5	Underweight
Between 18.5 – 25	Normal
Between 25 – 30	Overweight
Between 30-40	Obesity
Greater than 40	Morbid Obesity

Calculate BMI Yourself

Would you like to calculate the Body Mass Index yourself? The Body Mass Index or BMI is a formula based on height and weight used worldwide by health professionals such as personal trainers, doctors, dieticians, to assess someone’s body weight. To calculate the BMI, we need some data from the body, namely gender, weight, age, and height. There is a difference between men and women. Women generally have a higher body fat percentage than men. In addition, the BMI index is valid for adults aged 18 to 70. Because not every person is the same, some groups of people of Asian descent have different values for boundary values. The same applies to children, who have a different boundary value. The explanation for this is that they have a different body build. If these population groups and children show unhealthy values, this can indicate an increased risk of health problems. Your Body Mass Index number gives you an indication of whether you are too light, normal, too heavy, or much too heavy. The BMI is a broad gauge of health for the average person, including their total body fat percentage, and can serve as a predictor of health problems caused by being overweight and obese. In short, the higher your BMI number, the greater the risk of health problems. If your value is lower than 18, the advice is often to try to gain weight. When the BMI is between 18.5 and 25.5, this is often seen as a healthy index and it is often recommended to maintain this weight. The borderline cases at the top are around 30. If the BMI exceeds 30, the advice is often to try to lose weight, because health risks such as heart disease, vascular disease, and high cholesterol levels are then looming. Also read the article: the Body Mass Index is outdated

Definition of Body Mass Index

• Overweight is excessive body weight, including fat, muscle, bones, and water.
• Obesity, morbid obesity, and severe overweight are an excess of body fat.

An athlete or muscular person can be overweight without having obesity.

BMI calculator

Unfortunately, the Body Mass Index as a health indicator is not foolproof. With the BMI calculation, it is for example possible to be overweight, even if you are muscular and have a low body fat percentage. In that case, your body fat percentage is a better indicator. The BMI is the weight of a person divided by the height squared: BMI = kg/m2. The values you need to calculate your BMI are:

• Your weight in kilograms
• Your height in meters (or centimeters, see below)

For example, you are 1.57 meters tall and weigh 65 kilograms. Your BMI is: 65 / (1.57 x 1.57) = 26 You can also use centimeters. The same calculation is then: 65 / ((157 x 157) x 10.000) = 26 For convenience, we have placed a simple BMI calculator on this page. This calculator uses the second method of calculation, with centimeters. [fcp-bmi-calculator]

What is a healthy BMI

The United States government has determined in 1998 that a healthy weight is a BMI between 20 and 24.99. A BMI between 25 to 29.99 is now considered overweight. Due to the limited calculation, the Body Mass Index is not a measure of your overall health. That BMI does not take into account muscle mass, fat mass, or bone mass. Because every person is built differently, weight can also be composed in different ways. If you want to be sure whether your height and weight can be categorized as healthy, you better measure your body fat percentage. The body fat percentage says more about the amount of fat mass you have on your total body. In the past, you had to measure your body fat percentage using various measurement points, tables, and a skinfold caliper. Nowadays, you have electronic skinfold calipers that do the calculation for you. Then you only need to measure the skinfolds and the calculation for your body fat percentage is done for you. Moreover, the BMI is based on Western body types. Often you see that people of Asian descent get completely different BMI results than Europeans or Americans. It is not said that their health is less than that of Europeans.

Okay, I’ve calculated my body mass index. Now what?

Your BMI number doesn’t mean much if you don’t know what that number stands for. The official guidelines are as follows (numbers differ slightly between sexes):

Classification of body mass index calculation

Obesity Class 1 means you are very overweight, the risk of becoming ill as a result is high, and you need at least 5 to 10 percent weight loss. Obesity Class 2 means the risk of becoming seriously ill due to overweight is very high, and you can even die from it! It is recommended to contact the doctor.

BMI and health risks

A high BMI means you are more susceptible to certain weight-related diseases. By knowing your BMI, you can do something about it, so you are less likely to get those diseases. Some of those diseases are:

• Heart and vascular diseases
• Diabetes
• Infertility (in women)
• Incontinence

The health risks related to your BMI are:

Limitations of the BMI

Your body build is also not taken into account in the calculation, so a short but heavy-built person with not much fat can still come out of the BMI as too heavy. The BMI is not a good method to calculate the health status of:

• children; the BMI calculation is based on adults
• athletes and bodybuilders; the calculation does not take muscle mass into account
• pregnant women: have more body fat
• people over 65; a higher BMI may be better for them to cope with diseases

Another method that works well in combination with the BMI is measuring waist circumference.

Disadvantages of BMI calculation

Naturally, there are also disadvantages when calculating BMI values. One of the obvious disadvantages is that it is assumed that every body is built the same and that subsequently the value between height and weight can indicate whether someone has a healthy weight or suffers from underweight or overweight. This overlooks specific groups such as athletes whose bodies are characterized by a lot of fat-free muscle mass. According to the BMI calculation, athletes often suffer from overweight. This is absolutely not correct and makes BMI measurement inaccurate for athletes. But the reverse can also occur. People with a healthy weight can still come out with an outcome indicating overweight according to this calculation. In a study published in 2008, it was found that 25% of people in a test group would come out with overweight as a result of a BMI calculation. With a body fat meter, this percentage turned out to be higher than 40%. So if you really want to know how healthy your weight is relative to your height, measure your body fat percentage using a body fat meter. Another disadvantage of the BMI is that it does not look at someone’s body build. In another article, we described the different body types, ectomorph, mesomorph, and endomorph. Someone with an ectomorph build can have a lot of fat and still come out with a healthy score according to the BMI calculation. And vice versa, it can also apply to an endomorph with little body fat, who can still end up with an unhealthy score.

BMI in the elderly

The BMI is an index that serves as a guideline for adults between the ages of 18 and 70. There are different values and therefore guidelines for people over 70 years old. Various studies have shown a relationship between the Body Mass Index and mortality in the elderly. Results from these studies indicate that the lowest mortality in the elderly occurs when the BMI is higher than the BMI for adults. This could mean that different guidelines should be followed at a later age. Because many changes occur in body build, body fat percentage, and overall health in the elderly, different advice than BMI is in place. The medical basis is therefore to maintain weight and to exercise sufficiently to maintain muscle mass. Losing weight is only advisable if this has been found to be good in consultation with the doctor.

Conclusion

Above you have been able to read about the history and application of the body mass index. It is a fairly simple way to determine whether you have a healthy weight or whether you are underweight or overweight. It is limited in addition to the simplicity, also a way to determine your overweight. After all, it does not take into account factors such as bone mass, muscle mass, and fat mass. To further investigate your health, a BMI outcome alone is not sufficient. If you have an undesirable outcome of your BMI, you should further investigate your body fat percentage and fat-free muscle mass.