- Some experts say body mass index (BMI) is a good starting point for people to assess their overall health.
- Critics, however, say the measurement is outdated and discriminates against women and People of Color.
- The best advice is to use BMI as a tool to determine if you need other tests, or if you need to change your diet or exercise routine.
It’s a common practice for those focusing on weight and health: Clicking on an online tool to estimate your body mass index (BMI).
But for a segment of the population like People of Color, including those of Asian descent, as well as many athletes, BMI results may not represent your true health at that moment.
Still, obesity and weight-health experts say BMI is a worthy data point to help guide the overall treatment of patients.
“BMI is a great tool for the population in general,” Dr. Caroline M. Apovian, co-director of the Center for Weight Management and Wellness at Brigham and Women’s Hospital in Boston, told Healthline, “but it breaks down somewhat in some individuals.”
Case in point: National Football League player Rob Gronkowski’s BMI comes in at 30.6, which is considered obese. That’s because the BMI doesn’t know he’s muscular, quite tall, and has six-pack abs.
BMI can be off, too, in
Some ethnicities, like those of Asian descent, can develop signs of type 2 diabetes at a lower BMI than the estimator chart would put them. Obesity is a risk factor for type 2 diabetes.
“The BMI is an outdated, racist, and sexist ratio of weight and height that was never intended to assess or diagnose an individual’s medical status,” said Samantha DeCaro, PsyD, a licensed psychologist and assistant clinical director at The Renfrew Center of Philadelphia who specializes in eating disorders.
“The BMI perpetuates the myth that people in larger bodies are always at risk for health problems and those in smaller bodies are not. For that reason, the BMI hurts every body,” DeCaro told Healthline.
Apovian said when used as designed — as a screening tool and not a diagnostic tool — the BMI remains a useful starting point.
“The average person in the United States is not doing a lot of physical activity, so for the average person, it’s a very good measure,” she said.
So why are some pushing back against it?
Dr. Silvana Obici, chief of the endocrinology and metabolism division of the Stony Brook University Renaissance School of Medicine in New York, said that it could be that when we hear our BMI or use a tool to check it on our own, bias enters the fold.
“I think the issue is people just (checking it via a tool or program) on their own,” and then making medical assessments from that, Obici told Healthline.
Even the word “obese” brings bias and self-bias she said, which is why she’s both moving away from using them and at the same time reminding both patients and professionals that the BMI “is a starting point for functional health” and not a diagnosis.
BMI can help a medical professional decide what paths to pursue in checking a person’s health, Obici said.
“It’s only the tip of the iceberg, but it’s useful to start the conversation,” she said.
“The problem is people want this one marker (to assess their weight health), and that just does not exist,” Dr. Holly Wyatt, a professor with the UAB Department of Nutrition Sciences, told Healthline. “Like any test, if you do not understand the rest (of what may be going on), you cannot use it as a (decision driver).”
“There’s a lot of baggage with weight,” Wyatt added. “It’s not like blood pressure and blood glucose, which people don’t usually equate with self-worth. Things around weight can send us down a path we don’t need to go down.”
That’s why, Wyatt said, the best thing a person can do with the BMI is ask their medical team how they should feel about their measurement and if any further testing is called for.
“BMI is a ‘risk factor stratifier,’” said Wyatt.
In other words, your medical professional can base more testing (if needed) and actions (if called for) based on the BMI as a starting point.
One more thing she’d like the world to stop doing? Using BMI as a weight or fitness goal.
“Losing weight is not about getting your BMI down below 25,” she said. “It’s a (data point), not a goal.”