The body mass index: What’s the use?

The body mass index (BMI) is a ubiquitous metric frequently used in body image research: as a correlate, covariate, descriptor, and more. However, the racist history of the measure is often unknown or unacknowledged. BMI was coined by Ancel Keys who used Adolphe Quetelet’s statistics of weight and height, later becoming a measurement of so-called “health.” Eugenics founder Francis Galton used Quetelet’s statistics to determine the abnormal, in a concerted effort to eliminate bodies seen as “unfit.” The BMI has been used to compare bodies to white masculinist ideals for decades (e.g., in insurance coverage, healthcare access), which is something body image scholars must reckon with if our collective goal is to subvert unrealistic, harmful, and damaging beauty ideals—not inadvertently validate them. In body image research to date, BMI use/usefulness helped unpack the complex relationship between negative and positive body image(s): BMI is consistently related to both. However, it has also been overused, and we argue—uncritically and inappropriately used—since it misses the root issue: fat discrimination and weight stigma. Thinking with critical race theorist Sara Ahmed’s (2019) work on “use,” we open a conversation on the potential implications of use/disuse of BMI. We outline the use, usefulness, and used-upness of BMI and offer reflections on what it means to be a critical user or outright refuser of this metric.