Bye-bye, BMI

Monday, September 14, 2020 - 10:12am

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Design courtesy of Ahmad Kady

More and more people and health care professionals are coming to the realization that the Body Mass Index, more commonly known as BMI, is largely useless when it comes to assessing one’s health and using it as a weapon to try and shame individuals into losing weight does much more harm than good. The harm of weight stigma, a term that describes the institutional, systemic and person-to-person discrimination faced by individuals with larger bodies, is becoming well-documented. These findings dispute the longstanding belief that being “overweight” or “obese” in itself makes someone unhealthy and instead suggest the stigma that comes with being a member of these socially constructed categories takes a negative toll on one’s physical health just as it does their mental health. Moreover, bias from health care providers often leads to poorer quality care of larger-bodied folks, further perpetuating the cycle.

Yet for some reason, BMI is being used as a grade in some American schools; I was shocked to learn of this through a podcast I listened to this summer. I find this new use of BMI — one of a grading system by which young children perceive their worth — to be outrageous, especially since it’s happening at the same time as the movement to move away from BMI. 

The BMI scale has numerous limitations weighing it down: It is not meant to be used as an indicator of health. Rather, it was created by a statistician who was trying to gather data on the weight of the population; it was not meant to be used on an individual level. BMI is also not inclusive of non-European nationalities and ethnicities, meaning it is unsubstantiated as a viable measure for other people (e.g. Black, Indigenous and people of color). More people might also be aware that BMI doesn't account for muscle mass, as this appears to be the most highlighted limitation of BMI in the media lately. Many elite athletes fall under the “overweight” and even “obese” category simply because they have a lot of muscle, and muscle is denser than fat. For example, by BMI standards, Dwayne “The Rock” Johnson is “obese,” and many great athletes fall under the “overweight” category. 

More importantly, BMI is rooted in a toxic diet and fitness culture. It serves to remind individuals that their body is in need of “fixing,” and for children and adolescents, intervention programs targeting BMI often lead to disordered eating behaviors. Using BMI to determine the state of one’s health sends a message that the only way a person can be “overweight” or “obese” and still healthy is if it is due to their high muscle mass. That’s not the case. On the whole, BMI is not useful in determining health, and making people hyper-aware of their BMIs with the supposed intention of urging them to be healthier only damages their mental health. 

Let’s turn our attention to the turmoil on the flipside with youth and students. Those whose BMIs don’t fall under the ill-defined ideal range are receiving the message that they have failed in some regard when they receive a bold, red BMI number equivalent to an “F.” These students face a heightened risk for bullying and teasing. The blow to their self-esteem and increased body dissatisfaction may likely put them on a life path of “yo-yo dieting” that only worsens their physical and mental health. Finally, with BMI report cards, body shaming is covertly perpetrated under an institutional system, and worse, at an extremely tender life stage.

Beyond these limitations, there are various reasons why BMI is harmful to children and adolescents specifically. The psychological damage the construct can inflict on vulnerable populations, including children, adolescents and young adults, is of great magnitude. Students, from elementary school to maybe college, may rely on report card grades to define themselves because they have yet to navigate the aspects of their true self that define their worth: If you’re an “A” student, you’re a good one. If your GPA is honors level, you soak in the applause from your family members and cherish the status it brings you. An ideal BMI is just something to add to the list, conveying the message that you’re acceptable and worthy. And don’t get me wrong, you most definitely are. But that’s in no way related to your BMI. 

Even those who attain a socially favorable BMI on their report card can fall into the dangerous trap of basing their self-worth and confidence on their number. This is problematic because the fact is, your weight is going to fluctuate throughout your life. If you start perceiving a lower fluctuation as success and a higher one as failure, you’re in for a lifetime of feeling miserable and at war with your body. So, the focus on BMI is also problematic for those who are in the ideal range. It’s a lose-lose situation if there ever was one.

But if true health is the concern, a weight-neutral approach focusing on healthy behaviors is the way to go. Instead of targeting the number on the scale through restriction, which increases the likelihood of depression and eating disorders, encourage children to explore movement and find physical activities and sports they enjoy. This approach deters them from going down the path of toxic fitness culture. Children and adolescents should also be focused on adding nutrient-dense foods into their diets and remove focus from what they should take out. 

Still, BMI report cards are the reality in many American schools, reflecting the deeply rooted fatphobia in our society which, at the individual surface, presents as a fear of “becoming fat.” This fear is reinforced by how poorly people in larger bodies are treated in our society and the assumptions made about one’s personality when they are in a larger body (e.g. that they are lazy or that they “overeat”). With this in mind, it’s understandable why schools and parents, wanting the best for youngsters, have become fearful of their kids gaining weight. Their fear of and utter aversion to their kids falling beyond the narrow ideal category is rooted in an effort to protect children and adolescents from cruel treatment from society. 

It’s time to do away with BMI report cards. They are the exact report card that belongs at the bottom of the trash. Their focus on weight, a micro piece of the much larger and multifaceted puzzle that is health, provides no benefits. Instead, if a youngster’s true health is a cause for concern, targeting their behaviors through mindful eating practices and the exploration of enjoyable movement is a much better lifelong approach. 

Nyla Booras can be reached at nbooras@umich.edu.