11 May, 2023

What Is BMI and Why Is It Used As A Metric?

We frequently hear the term BMI used in regard to individuals in terms of their weight. What is BMI and what is it used for? The term BMI stands for body mass index and is a measure of a person’s weight in relation to their height. It is used as a simple and quick tool to determine whether an individual has a healthy body weight, and it is calculated by dividing a person’s weight in kilograms by the square of their height in meters.

Where Did The BMI Calculation Come From?

In the early 19th century, Lambert Adolphe Jacques Quetelet, a professor of mathematics and astronomy at the Royal Observatory of Belgium, was involved in a government project collecting and analyzing data on the country’s population.
He needed a simple, standardized way to measure people’s body composition in order to put them into categories. He recognized that weight alone was not a reliable indicator of overall health, as it did not take into account differences in height. Therefore, he developed the Quetelet Index as a way to standardize the measurement of body weight in relation to height.

This allowed him to compare the body compositions of individuals across different populations and to identify patterns and trends in human growth and development. The Quetelet index is what we know today as the BMI chart.

What Is BMI Used For?

Over time, the BMI index became widely used as a tool for assessing individual health, particularly as rates of obesity and related health problems began to rise in many parts of the world.

Today, the BMI chart is one of the most commonly used measures of body weight utilized as a metric by healthcare professionals, researchers, health insurance companies, and the general public because it provides a convenient way to categorize individuals into different weight categories.

BMI levels are important because they are used as a benchmark in the healthcare industry and may affect your treatment plan or your insurance coverage. Higher BMI levels (40+ or morbid obesity) are associated with an increased risk of disease.

An individual’s BMI is taken into consideration when being evaluated for a surgical procedure. Additionally, many insurance companies use a patient’s BMI range to determine eligibility for certain procedures or surgeries, such as bariatric surgery like gastric bypass.

BMI categories: underweight, normal, overweight, and obese

How To Calculate BMI

An individual’s BMI, or body mass index, is calculated by dividing their weight in kilograms by the square of their height in meters. The formula for calculating BMI is:

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

This calculation results in a numerical value that is used to categorize individuals as underweight, normal weight, overweight, or obese. If you wish to know your BMI, there is no need to do the math yourself, use our BMI calculator!

These categories are based on the World Health Organization’s (WHO) classifications, which have been established based on a large body of research linking BMI to a range of health outcomes.

Standard WHO BMI Ranges Chart
Weight Classification BMI Numerical Range
Underweight less than 18.5
Healthy weight 18.5 to 24.9
Overweight 25 to 29.9
Moderately obese (Class I) 30 to 34.9
Severely obese (Class II) 35 to 39.9
Morbidly obese (Class III) 40 or above

Are There Differences In A Healthy BMI For Women vs. Men?

The same BMI ranges are generally used to determine a healthy weight status for both men and women. However, there may be some differences in how BMI is interpreted for men and women due to differences in body composition and other factors.

On average, men tend to have more muscle mass and higher bone density than women, while women tend to have higher levels of body fat. As a result, women may have a higher BMI than men for the same amount of body fat.

In addition, the health risks associated with BMI may vary between men and women. For example, studies have found that a higher BMI is associated with a greater risk of type 2 diabetes in men, while in women, a higher waist circumference may be a better predictor of diabetes risk than BMI alone.

Is BMI An Accurate Measurement Of Health?

The BMI chart, like any measure of body weight, has some limitations when it comes to determining an individual’s health. Some of the main shortcomings of using BMI to assess health include:

1. It does not account for differences in body composition
BMI is calculated based on an individual’s weight and height, but it does not distinguish between different types of body mass, such as muscle versus fat. This means that people with a higher percentage of muscle mass, such as athletes or bodybuilders, may have a high BMI even though they are not overweight or obese.
2. It may not be accurate for certain populations
BMI is based on data collected from predominantly white populations and may not accurately reflect the body composition of people from different racial or ethnic backgrounds. For example, people of South Asian descent may have a higher percentage of body fat at a lower BMI than people of European descent.
3. It does not account for differences in age or gender
BMI is calculated the same way for men and women of all ages, even though body composition and health risks can vary depending on age and gender.
4. It may not capture other health risk factors
BMI is just one measure of health risk and does not account for other factors such as a family history of the disease, lifestyle habits, or other health markers such as blood pressure, cholesterol levels, or blood sugar levels.

Overall, while BMI can be a useful tool for assessing weight status in populations, it should be used in conjunction with other health markers to gain a more complete understanding of an individual’s overall health status.

Why Do We Still Use The BMI Chart?

While it has its limitations, the BMI chart remains a widely used metric for various reasons, including:

  • It is a simple and easy-to-use tool for assessing a person’s weight status. It only requires two pieces of information: height and weight, which are readily available and easy to measure. This makes BMI a quick and convenient metric that can be used by healthcare professionals, researchers, and the general public to assess weight status.
  • It does not require any special equipment, and it is an inexpensive method of predicting an individual’s risk for chronic health conditions.
  • BMI has been linked to a range of health outcomes. Research has shown that individuals with a high BMI are at increased risk of developing a range of health problems, including type 2 diabetes, cardiovascular disease, high blood pressure, and certain types of cancer. By using BMI as a metric, healthcare professionals and researchers can identify individuals who may be at risk of developing these health problems and take steps to prevent or manage them.
  • BMI is a useful tool for tracking changes in weight over time. By regularly measuring BMI, individuals can monitor their weight status and make adjustments to their diet and exercise habits as needed to maintain a healthy weight.
  • BMI is a widely recognized metric that is used internationally. This makes it a useful tool for comparing weight status across different populations and for assessing the prevalence of overweight and obesity at a global level.

An individual’s BMI is easy to calculate and interpret, making it a convenient tool for healthcare professionals and individuals alike. Although it is not an accurate depiction of a person’s health, it can be used as a starting point for discussions about weight status and potential health risks associated with other than healthy BMI numbers.

Reveal Weight Loss Can Help You Reach A Healthy BMI

If you have a high BMI and are experiencing weight-related conditions, contact Reveal Weight Loss today.  Our team of skilled professionals can tailor a plan to meet your needs and provide the level of support you require to become healthier.

We will create a customized plan of care for you utilizing not only your BMI but other factors such as your age, gender, body composition, and lifestyle factors to ensure you achieve sustainable weight loss.

Set up a consultation with one of our knowledgeable team members today to learn about options for weight loss that are safe, effective, and do not require surgery. Make that first big step on your weight loss journey and contact us today!