What’s the Scoop on Body Mass Index?
By: Erin Oberman, Masters Level Intern
Many folks experience the same routine at their annual primary doctor visits: you get your blood pressure, height, and weight taken, followed by your doctor relaying your BMI (body mass index) is too high and therefore you need to lose weight.
History
Body mass index was invented nearly 200 years ago by a man named Adolphe Quetelet, who studied astronomy, mathematics, statistics, and sociology. Quetelet believed that the mathematical mean of a population was its ideal, and the way he proved this was by the invention of the BMI. Originally called Quetelet’s index, Quetelet based his findings solely on the size and measurements of white, Western European males. By the turn of the next century, Quetelet’s index would be used as scientific justification for eugenics, which is a set of beliefs and practices that aim to improve the genetic quality of a human population by excluding people and groups judged to be inferior.
Fast-forward to the 1970’s a researcher by the name of Ancel Keys conducted a study of 7,500 men from five different countries with the goal of finding the most effective way to measure body fat. Like Quetelet’s work, Ancel Keys pulled subjects from predominately white nations, resulting in whiteness taking center stage for their research findings. Keys and his research team set out to test which diagnostic tool was the best to measure body fat. They found that the BMI was the strongest of three weak measures, alongside water displacement and skin calipers. Keys renamed the Quetelet’s index the “Body Mass Index.”
In 1985, the National Institutes of Health redefined the term “obesity” and tied it to individual patient’s BMIs. In 1998, The National Institute of Health changed their definitions of “overweight” and “obese” again by lowering the threshold of what it means to be medically considered fat. By the turn of the millennium, the BMI has become “part of the routine” at doctor visits as the “Obesity Epidemic” took America by storm without acknowledging the change in definition that led to startling spikes in patient charts.
Present Day
Today, the BMI is a tool used widely to measure one’s health, yet there is growing criticism that the tool doesn’t take body composition (fat vs. muscle) into account, along with growing body of research stating a person’s weight shouldn’t be the reason someone is deemed healthy or unhealthy. Many argue clinicians must take all of a person’s health markers into account when determining one’s health status instead of only considering single factors such as muscle mass or body fat percentages. This would include patient backgrounds, stress levels, access to food and dietary habits, relationship with movement and any underlying health concerns or conditions.
These measures and current BMI definitions were built by and for white males, proving to be even less accurate for people of color and women. Body composition, including percent body fat or muscle mass, can vary by race and ethnic groups, which can lead to misdiagnosis and mistreatment. Despite all proven inaccuracies, the BMI continues to be used as a measure of health, resulting in marginalizing people in larger bodies.
References
Gordon, A. (2019, October 18). The bizarre and racist history of the BMI. Medium. Retrieved February 28, 2022, from https://elemental.medium.com/the-bizarre-and-racist-history-of-the-bmi-7d8dc2aa33bb
Rothman, K. BMI-related errors in the measurement of obesity. Int J Obes 32, S56–S59 (2008). https://doi.org/10.1038/ijo.2008.87