Body mass index has become an obsolete method of measuring health (Image by Ketut Subiyanto)

What is BMI? What Are the Drawbacks of Using It to Measure Health?

The body mass index (BMI) is a calculation that analyses your height and weight to determine whether you are at a healthy weight or not. BMI is determined by multiplying a person's weight in kilogrammes by their height in metres. A BMI of 25 means you weigh 25 kilograms per square meter.


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How precise is BMI?

Body mass index considers natural differences in body form to determine a healthy weight range for a given height. Because muscle is substantially denser than fat, extremely muscular individuals, such as heavyweight boxers, weight trainers, and sportspeople, will be considered obese if referred to only BMI as a health indicator.

Therefore, healthcare providers usually consider other indicators in addition to your BMI when determining if you're at a healthy weight.

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Why is BMI ineffective and misleading?

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The BMI is an imprecise estimate of body fat content since it ignores muscle mass, bone density, total body composition, and racial and sex disparities. The BMI calculation is so straightforward that almost anyone can use it.

However, because it simply considers your height and weight, it is erroneous due to its simplicity. More information than simply your height and weight is needed to determine whether or not you are overweight. Here's a list of all the ways the BMI formula might go wrong:

How Much Muscle You Have: It doesn't matter if you are healthy. The more muscle you have, the higher your BMI.

Frame Dimensions: A person with a large frame has a higher BMI, even if otherwise healthy.

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Gender: Women typically have greater body fat than men with the same BMI.

Age: An older person will often have more fat than a younger person with the same BMI.

Muscle: Athletes have lower body fat percentages than non-athletes with the same BMI.

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Even if you're not overweight or obese, your BMI calculation may indicate that you are, especially if you're exceptionally muscular, pregnant, or have a huge frame. This is why this health indicator has become obsolete.

Apart from just depending on BMI, it's better to use several other measures to determine how healthy your weight and body fat are, such as waist-to-hip ratio and body fat percentage.


Is BMI no longer relevant?

Because researchers may easily get the measurements needed to compute BMI, it has proven to be a useful research tool for large populations. However, its applicability to individuals or small groups has been questioned.

There is a strong push to eliminate BMI as the sole indicator of a person's weight status, and insurance companies may follow suit in the future. More significantly, there's no reason to rely just on BMI when you and your doctor examine your current health state because there are so many other, more effective health indicators.

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However, there are some advantages of using BMI

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The BMI works well for what it was originally designed to do: quantify obesity rates in a huge population. Since it's a reasonably straightforward method to quantify obesity in a community, it makes it easier for health researchers to collect data on big groups.

For example, researchers can easily conduct studies on how dietary habits influence obesity risk in big groups of people using data from BMI. Because it is not prohibitively expensive to assess — unlike, say, body fat measures — researchers can look at larger groups of study subjects to identify trends in wider populations.

BMI can also help your doctor determine your overall risk of obesity-related disorders. However, it's preferable to use it with other metrics to get a more comprehensive picture of your health. You can use an online BMI calculator to complete the calculations for you. A BMI of 18.5 to 24.9 is a healthy weight range.


Takeaway

To assess your weight and health, take a more holistic approach and use many measurements apart from BMI. Consider your waist size and your BMI to make sure you're under the acceptable waist size for your gender. Instead of looking at your weight reduction in terms of your BMI, consider a combination of pounds and inches lost and a professional body fat measurement to see whether you have a healthy body fat level.

Focus on performance-based goals rather than merely wanting to fall into a set BMI range to stay motivated and happy with your health regimen. Instead of being able to check the "normal weight" box, reward yourself for cooking healthy meals at home for the week, running faster without losing your breath, or lifting a higher weight during your workouts.

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Edited by
Sabine Algur
 
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