Summary: A growing number of researchers are calling for the end of BMI as a measure of health, arguing it’s outdated, misleading, and rooted in discrimination. The metric, a simple weight-to-height ratio, fails to account for fat distribution, muscle mass, age, or ethnicity—yet it still influences medical decisions and public perception.
A new study urges policymakers to stop relying on BMI and instead focus on holistic indicators of wellness. The researchers emphasize that redefining health is essential to reducing stigma and improving care across diverse populations.
Key Facts:
- Outdated Measure: BMI was never designed as a health tool and fails to capture true body composition.
- Harmful Consequences: Reliance on BMI reinforces stigma and restricts medical access for many groups.
- New Direction: Researchers recommend replacing BMI with metrics that better reflect overall health and well-being.
Source: University of Waterloo
As new Statistics Canada data reveals that two-thirds of Canadians are considered overweight or obese, researchers are urging the public and policymakers to rethink how we define and measure health — starting with one of the most used metrics — the body mass index (BMI).
For decades, BMI — a simple ratio of weight to height — has been treated as a gold standard in public health and medical practice. It influences everything from fitness apps to clinical decisions about surgery eligibility and pain management.
But according to a new Waterloo-led study, BMI tells only a fraction of the story about a person’s health and does more harm than good when used.
“It is becoming more well-known that BMI doesn’t measure what many people think it does,” said Dr. Aly Bailey, the lead author of the study and a professor in the Department of Recreation and Leisure Studies at Waterloo.
“It cannot distinguish between muscle and fat, doesn’t account for where fat is distributed in the body and overlooks important factors such as age, sex and race. Two people can share the same BMI but have completely different health profiles.”
The researchers warn that BMI’s limitations have real-world consequences. It can influence access to medical care, reinforce harmful stereotypes about “normal” bodies, and contribute to stigma — particularly for people in racialized, disabled, older, or larger bodies.
Originally developed in the 19th century to statistically identify the “average man,” the BMI is a measure based on height and weight.
“However, what many people often don’t know is that the BMI was never created with health in mind at all,” Bailey said.
“Instead, it was a statistical tool used to justify racist and anti-fat ideas and other forms of discrimination. It quickly became a so-called measure of health, beauty, and fitness.”
Building on calls made by activists, the study outlines possible paths forward. One approach is to continue using BMI, but only with explicit recognition of its racist and problematic history.
Another is to consider more nuanced and valid measures of body size, or include indicators that track actual health outcomes. The other, bolder option, which the authors advocate the most strongly, is to reject BMI altogether.
Key Questions Answered:
A: It’s simple, fast, and widely adopted, but convenience has overshadowed its scientific limitations.
A: It doesn’t distinguish between fat and muscle, ignores fat distribution, and was developed using biased assumptions about the “average man.”
A: More holistic assessments—like metabolic health indicators, lifestyle factors, and body composition scans—offer a fairer picture of well-being.
About this BMI, health, and neuroscience research news
Author: Ryon Jones
Source: University of Waterloo
Contact: Ryon Jones – University of Waterloo
Image: The image is credited to Neuroscience News
Original Research: Open access.
“The body mass index: What’s the use?” by Aly Bailey et al. Body Image
Abstract
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.
