The Real Story Behind BMI
When I was as young as eight years old, I already dreaded going to the doctor. Not because of needles or strange medical equipment but because my doctor was already pulling out the BMI chart. Each visit, I would step onto the scale. The nurse looked at the number and read it in disgust, and a thick blanket of shame fell onto me. Later, the doctor came in, holding a laminated graph - the BMI chart - with her. She explained to me that I needed to lose weight because I was “off the BMI chart.” She fat-shamed me, scolding me to “watch what I eat and get more exercise.” That conversation would happen repeatedly every time I went to the doctor’s office. There was no mention of my asthma or other issues that prevented me from heeding her advice. She did not acknowledge the reasons behind my weight gain or the ongoing mental health issues. There was no mention to my mother of what she should do. It all fell on my pudgy eight-year-old shoulders and that thick blanket of shame has stayed around a long time.
I conveniently tucked away that memory for several years to process later with a therapist. I did not acknowledge the shame or ramifications on my body image until adulthood. Now, as I remember it, I feel enraged on behalf of that child who was an innocent causality in the atrociously fat-phobic medical system. How can doctors, who take an oath to “do no harm”, fuel fat bias using an arbitrary and medically useless number?
Let’s dive into the history of BMI, shall we?
The History of the BMI:
The origin of BMI can be traced to a Belgian statistician named Adolphe Quetelet in the 1830s (Humphreys 2010). Quetelet was essentially fascinated by the new theory of the bell curve that was invented in 1809 and wanted a way to easily describe the “average man” (Pray & Riskin 2023). Now, let’s be clear: this was the description of the average white, likely middle-class, European man of the 1800s. So, Quetelet found a formula that could produce a number based on easily attainable data points (height and weight). He was not a doctor, he did not even have an interest in medicine or anatomy. He just wanted an easy statistical way to define the average body size.
The Quetelet formula essentially fell out of view for over a century until the vice president of an insurance company, Louis Dublin, rediscovered it in the 1950s and started using the Quetelet formula to compare body size with health outcomes (Pray & Riskin 2023). Dublin was the first one to start ranking people on their BMIs and categorizing them into “small, medium, and large” and noted the correlation that people who are classified as “large” have higher medical costs. (Now, obviously, there is no way to prove that they used this information to increase insurance premiums for people considered “large” but, I mean, we can make our speculations.)
In the 1970s, a physiologist named Ancel Keys “rebranded” the Quetelet Formula into what it is today: the body mass index (BMI) (Pray & Riskin 2023). Keys was a researcher and publicly stated many times that BMI was a helpful tool for research studies due to the ease of measurement but provided much too simplistic a view of a person’s body to be used in medicine. He stated many times that BMI was just a tool to be used in conjunction with more accurate measurements (like waist-to-hip circumference ratio or skin-fold testing) and then analyzed with the rest of a person’s health picture.
As a quick aside: I would like to draw your attention to the fact that at this point, there were a few studies done to essentially replicate Quetelet’s study that were also done with now mid-20th century men. They had a slight improvement in representation, including a handful of Asian and Black men, and men from various socio-economic backgrounds. However, they did not include any women, children, or men of other races and the few Asian and Black men made up less than 1% of the studies. To this day, there is a severe under-representation of people who do not identify as cis white men in all BMI studies, and it does not appear to be changing any time soon.
Back to the story:
In the 1990s, the WHO decided to further explore BMI and gave it the categories we know today with cut-off scores to determine ‘normal’, ‘overweight’, and ‘obese’. The researchers at WHO are on the record as admitting that the cut-off numbers for each category are “arbitrary” (Flegal 2023). Before these categories were made and the term “obese” was constructed, obesity was not considered a medical concern. Multiple studies that interviewed doctors before the construction of the medical term “obesity” showed that doctors, by and large, did not view fatness as a medical issue but as a social or cosmetic issue (Flegal 2023).
But something else was happening in the late 1990s that would play a major factor in this story. Big pharma invented weight loss drugs, and the weight loss market was booming. Big pharma needed more people to buy their product, which meant getting it covered by insurance companies. To get it covered by insurance companies, obesity needed to become a disease. So in 2004, with the help of the WHO and the US government, obesity was now considered a disease risk factor that could be billable through insurance (Flegal, 2023). In 2013, a law was passed that allowed obesity to be considered a disease all in itself, further improving reimbursement rates and increasing big pharma sales.
That brings us to today where most doctors and other health professionals treat BMI to be as vital a reading as blood pressure. When I was working as a physical therapist at a major corporation, I was actually instructed by my supervisors that, in order to get reimbursed by Medicare, I had to get my patients’ BMIs for every evaluation I did - even though it had nothing to do with their physical therapy treatment. It is well-known across recent medical literature that BMI offers limited information on the full picture of a person’s health and it increases discrimination and bias for people who register as “large”, “overweight”, or “obese” on this arbitrary scale (Flegal, 2023). I have known a lot of people, especially women and gender non-conforming humans, who have faced undue discrimination based on the size of their bodies. People who have had serious medical issues got turned away because doctors were convinced that their issue was a product of their fatness.
Fat bias, just like racism and sexism, is a systemic problem. It is the medical institutions’ responsibility to address it. As a patient, if fat bias happens, you can request that your doctors specifically write in the documentation that they decline to do further testing because they believe it is due to body size. Or, you can ask them, “What treatment options would you do if someone with a lower BMI exhibited these symptoms?”
Personally, I feel I do not have the mental bandwidth to try to make lasting changes in our very broken medical system. The change I do hope to bring is helping the other casualties of this system, who also carry around their blankets of shame, to find a new way to approach their health.
There is so much more to health than weight or BMI. There is a reality where we feel good in our bodies and feel empowered to live confidently, no matter what arbitrary category we fall into.
Defining Health
Everyone should have their own definition of health based on their history and their personal goals. For instance, I have had asthma since I was 18 months old. For me, health does not look like running a 5K once a month. That’s not health - that’s an asthma attack. But it does look like being able to walk my dogs to the park and not feel wheezy. Sometimes to define what health is for us, we need to determine what it is not. How often do we set new years resolutions to “get more healthy”, only to lose a few pounds but have no real improvement in our quality of life? Good health is a good quality of life.
If you are interested in defining health for yourself, I would love to work with you and help you define what it looks like. Health coaching is a resource that helps you not only define health but also create realistic goals to get you there. It provides structure and tangible results to a topic that can feel very fluffy and abstract. It would be a pleasure to walk with you on your journey.
Schedule Your Complimentary 15-minute Intro Session at all-good-bodies.com
Sources:
Flegal K. (2023). Use and Misuse of BMI Categories. The AMA Journal of Medical Ethics,25(7):E550-558. doi: 10.1001/amajethics.2023.550.
Humphreys S. (2010). The unethical use of BMI in contemporary general practice. The British journal of general practice : the journal of the Royal College of General Practitioners, 60(578), 696–697. https://doi.org/10.3399/bjgp10X515548
Pray, R., & Riskin, S. (2023). The History and Faults of the Body Mass Index and Where to Look Next: A Literature Review. Cureus, 15(11), e48230. https://doi.org/10.7759/cureus.48230
