Body Mass Index (BMI) is bullsh*t… as a measure of health or a way to assess anything about an individual’s health status or growth process.
Eight reasons why Body Mass Index is a really bad, unscientific way to attempt to measure any individual’s health.
Note that linked sources are included, but they are not necessarily good website for those in eating disorder recovery to visit. Browse with care.
ONE: Quetelet—the theorist whose work eventually amounted to modern-day BMI—never intended his equation to be used for individual evaluation of health!
When considering whether or not a tool is effective, we must first assess the origins of the tool, and the tool’s original intentions. Invented by Adolphe Quetelet, modern-day Body Mass Index (BMI) was birthed from the statistical model of the “bell curve”, with Quetelet interested in applying the model to body size at the population level. In other words, Quetelet’s creation measures a population average, and is not meant to be generalized to an individual. In fact, Quetelet himself was only interested in whether or not it was possible to create a model demonstrating the theoretical bell curve of body size for the entire population. He never meant for his theory to be applied to individual persons, nor for his theory to go beyond just that: theoretical.
TWO: The inventor of BMI was a mathematician, not a medical doctor.
If you noticed that none of the above description mentions any kind of medical expertise, congrats! You’ve found issue number two: Quetelet was an astronomer and a mathematician. He had zero medical expertise. Why then would we think that this theoretical, statistical model would be a good measure of anything related to medical issues? Indeed, statistical models can inform medical care and research, but utilizing it to categorize risk associated with body size—the main application of the BMI—is shaky science at best.
THREE: Using the BMI encourages non-individualized, dismissive healthcare practices.
Even though Quetelet never intended his statistical theory to be used for healthcare, nor for individualized… anything… this is exactly what doctors do when they, for example: take your height and weight at the office; convert this information into a BMI number; and utilize that value to, in some cases, determine whether or not you are eligible to receive certain procedures. One such procedures is repairing a torn ACL. ACL repair is widely considered to be routine and low risk procedure regardless of body size. Though healing time may be impacted, there is no statistically significant difference between effectiveness of the procedure for different BMI classes.
Indeed, these BMI cut offs for routine procedures are put in place to protect the hospital from litigation because of the supposed “higher risk” of operating on someone above a certain BMI threshold. Instead of the patient’s health being the top priority, by using BMI as a marker of health—which many doctors offices currently do—the healthcare industry ends up protecting the monied interests over the patient. Ultimately, this results in doctors withholding necessary and life-improving treatment from patients.
FOUR: The growth projections utilized by the BMI scale were created 200 years ago by collecting data from white European men.
Because biodiversity is a fact of life, everyone’s “ideal body weight” will not match that of white European men from the 1830s.
See Taylor Rae Almonte-Roman’s detailed breakdown of the racist aspects of the BMI. Almonte-Roman’s piece also includes information about how the life-insurance industry adopted Quetelet’s model.
FIVE: It does not consider fat distribution, bone density, body composition, muscle vs fat, etc.
See point four!
SIX: It reinforces the pathologization and dehumanization of fat people.
Utilizing BMI, as has been explained above, contributes to weight stigma in the healthcare system. Fat patients often have a difficult time showing up to the doctor’s office because of the stigma they face. On top of that, when they do muster up the confidence to follow through on a doctor’s appointment, they may wind up not receiving the care they need, even though these services could be offered if other health markers were considered for procedure eligibility. This compounds the pathologization that is projected upon fat peoples’ body size.
SEVEN: BMI categorization changed overnight in 1998 to adhere to WHO guidelines.
These guidelines were partially developed by organizations and companies who make money via the weight loss industry) affecting almost 29 million Americans as “overweight” over night, illustrating the arbitrary nature of this tool.
Who did this benefit? Insurance companies who could now charge higher premiums, despite their customers not actually experiencing a decline in physical health.
EIGHT: The existence of the “obesity paradox.”
According to the obesity paradox, those at higher BMI’s have lower mortality if they do develop health issues versus those at the lower end of the BMI spectrum who develop health issues.
BONUS! The CDC themselves state on their website that the BMI is not meant to be used to, “diagnose… the health of an individual.”
In other words, even the CDC admits that BMI measures very little when it comes to an individual’s health status.
