The Body Mass Index (BMI) Is A Flawed System

When you were screened at your last checkup, your doctor may have classified you as healthy, overweight or obese based on your body mass index (BMI). Insurance companies consider a person’s BMI when deciding if they’re eligible for coverage for things like dietary counseling, weight-loss meds and bariatric surgery. But you may be surprised to learn that what we know today as BMI was actually invented by a white man nearly 200 years ago.

A Belgian mathematician named Adolphe Quetelet is credited with coming up with the measurement in the 1830s. BMI is determined by dividing a person’s weight by the square of their height. And because it’s easy to calculate, everyone from doctors to life insurance companies got with the idea of using BMI as a screening tool to determine whether or not a person is at risk for obesity.

According to the CDC, an adult with a BMI between 18.5 and 24.9 would be classified at a healthy weight. Between 25.0 and 29.9 is considered overweight, and anything over 30.0 is considered obese. That would mean that a person who is 5'9" would have to weigh between 125 and 168 pounds to be considered at a healthy weight. However, if they weight over 203 pounds, they would be considered obese.

But not everyone agrees that BMI is the best way to identify obesity. “BMI does not come from science or medicine,” said Dr. Fatima Stanford, an obesity medicine specialist at Massachusetts General Hospital. Dr. Stanford argues that BMI doesn’t consider the differences among ethnic groups. And because it doesn’t differentiate between muscle mass and fat, otherwise healthy athletes can end up being labeled as overweight.

And we haven’t even talked about the damage these kinds of labels can do to a person’s self-esteem. In 2016, an active middle school girl wrote a heartfelt letter refusing to participate in an assignment asking her to calculate her BMI, arguing the harm it can do to person’s body image.

”Ever since I can remember, I’ve been a ‘bigger girl,’ and I’m completely fine with that; I’m strong and powerful,” she wrote. But at the beginning of the year, I started having very bad thoughts when my body was brought into a conversation,” she wrote. “My doctor and I talked about my diet and how active I am. He did a couple tests and told me I was fine....My BMI is none of your concern because my body and BMI are perfect and beautiful just the way they are.”