Does Your BMI Really Matter? Is It Useful Or Useless?

How’s it going, guys? My name is Alex, and today we’re going to talk all about one of the most common ways of grouping people by their body weights: the Body Mass Index, or BMI. We’ll discuss what it is, how it’s used, if it’s a good measure, and some of the alternatives.

BMI has a lot of haters, and if you’re one of them, I’d love it if you read all the way to the end of this article for two reasons: so you can really understand the problems with BMI, and so you can understand why it’s still used so much and when it can actually be useful. I just want to point out that I’m not trying to recommend or advise against using BMI. I’m just going to talk about the science surrounding it so you have a better understanding yourself. Let’s get started.

What is BMI?

BMI was developed in the mid-1800s by Adolphe Quetelet, a polymath who founded the science of anthropometry—the measurement of human physical shape and sizes. Initially called the Quetelet Index, it became widely known as the Body Mass Index in the 1970s due to the work of nutrition researcher Ancel Keys.

BMI measures a person’s body weight in relation to their height. The formula is simple:

bmi formula

You guys can use our BMI Calculator for more accurate results

For example, if someone weighs 75 kilograms and is 1.78 meters tall, their BMI is 23.7.

BMI Categories

BMI alone doesn’t tell us much, so scientists have created categories:

  • Normal: 18.5 – 24.9
  • Underweight: Below 18.5 (with severe underweight below 16)
  • Overweight: 25 – 29.9
  • Obese: 30 or above, with further classifications:
    • Class 1: 30 – 34.9
    • Class 2: 35 – 39.9
    • Class 3: 40 or more

These categories are medical terms used to categorize people based on weight relative to height. They help in understanding health trends and potential risks.

The Utility and Limitations of BMI

BMI is a quick, cheap, and easy tool used in medicine for identifying if someone is in a weight category that might put them at risk for health problems like diabetes. However, it’s important to understand that BMI is not a comprehensive measure of health. It doesn’t account for body fat percentage, fat distribution, or muscle mass.

For example, individuals with high muscle mass, such as athletes, might be categorized as overweight or obese by BMI standards, even though they are exceptionally healthy. Conversely, someone with normal BMI might have unhealthy levels of body fat and low muscle mass, a condition known as sarcopenic obesity.

Weight Stigma and BMI

Weight stigma is discrimination based on weight, which can be exacerbated by BMI categories. Some healthcare providers may attribute health issues solely to a patient’s weight, potentially missing other underlying problems. This can deter individuals from seeking medical care due to fear of discrimination.

Alternatives to BMI

To get a better picture of someone’s health, additional measures can be considered:

  • Waist-to-Hip Ratio or Waist-to-Height Ratio: These measures help understand fat distribution, particularly abdominal obesity, which is linked to higher risks of cardiometabolic diseases.
  • DEXA (Dual-Energy X-ray Absorptiometry): A technique that uses X-rays to measure body composition, including muscle mass and body fat percentage. Though accurate, it is expensive and typically available only in large hospitals or universities.

Why BMI is Still Popular

Despite its limitations, BMI remains a popular tool because it’s easy to measure and useful for identifying health trends in populations over time. For instance, the average BMI in Europe and the U.S. has been steadily increasing since the 1970s, reflecting a rise in body fat levels.


BMI isn’t entirely useless, but it does have significant limitations. It’s a starting point that provides some information but shouldn’t be used as the sole indicator of health. Understanding its context and complementing it with other measures can give a more complete picture of an individual’s health.

If you have any questions or comments, I’d love to hear them. Please drop them below. And don’t forget to bookmark our website for more updates

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