The Misleading History of Body Mass Index (BMI)
BMI is used by respected medical organizations around the world. We also see its use in places such as gyms and research organisations. Despite this, BMI does not tell the full picture of someone's health. Let’s explore some of the limitations of BMI.
Throughout history, the language around weight gain and the challenges associated with weight loss has evolved. And in the early 19th century, a particularly large cultural and medical shift took place. The concept of BMI was introduced.
What Is BMI, and How Does It Work?
BMI was introduced by a Belgian mathematician and astronomer named Lambert Adolphe Jacques Quetelet in the 1830s. Then, in the 1970s, it was popularised by Minnesota physiologist Dr. Ancel Keys. He was looking for a more straightforward way to show body fat percentages than the methods used by insurance companies at the time.
The BMI calculation works like this:
Step 1: Take an adult’s weight in kilograms
Step 2: Divide by the square of that adult’s height in meters
Quetelet posited that a BMI below 18.5 indicated a person was underweight. A BMI between 18.5 and 24.9 was supposedly in the “normal” range. Between 25 and 29.9 was the “overweight” range and 30 or over was the “obese” range.
Today, BMI is used by respected medical organizations around the world. We also see its use in places such as gyms and research organisations. Despite this, BMI does not tell the full picture of someone's health. Let’s explore some of the limitations of BMI.
The Problems With the BMI
There are quite a few problems with BMI, dating back to its creation. The first is that Quetelet, the creator of the BMI, was not a physician. He was a mathematician. Here are some additional glaring problems:
Muscle Is Heavier Than Fat
Someone who lifts weights regularly or who has a genetic predisposition to higher muscle mass will have a higher percentage of their body weight which can be attributed to muscle mass. In fact, muscle is approx 15% denser (or heavier) than fat. Muscle, therefore, contributes to a higher BMI. People with heavier bone mass have the same problem since bone is even denser than muscle.
BMI Does Not Account for Ethnicity
BMI was initially based on White (Causacian) populations. However, we now know that certain ethnicities, like Asian populations have a lower BMI cut off such that a BMI 23-24.9 is considered overweight and BMI 25 is considered obese vs white populations where BMI of 23 would be considered “normal weight”.
Over Reliance on BMI as a measure of cardiovascular risk
The BMI is a very simple calculation. Used alone, it doesn’t tell us anything about where the fat is distributed (i.e. around the abdomen or around the hips) or cardiovascular fitness. As a result, it is not all that useful for determining overall metabolic health when used alone.
BMI Was Created 250 Years Ago
Finally, think of the amount of scientific and medical advancement that has occurred in the last 250 years. We know SO much more now about our bodies and how they function. Reliance on a centuries-old methodology created by a man without a medical degree is foolish at best.
Beyondbmi and Our Mission
Beyondbmi was created by doctors, scientists and clinicians who understand that archaic methodologies such as BMI do not give us enough insight into our clients and what they are dealing with. If you are someone who struggles with the challenges of managing their weight and want a more 360 degree way to assess your health, Beyondbmi is here to support you.
At Beyondbmi, we begin with your biology. We combine doctor-prescribed medication with nutritional therapy and one-on-one accountability coaching, all delivered by a multidisciplinary team of world-class experts. Book a free consultation today with Beyondbmi to learn more about how to gain health through the biology of weight loss.
Dr Harriet Treacy
Beyondbmi Co-Founder & CEO
