What is happening?
On June 14, the American Medical Association announced its recommendations for doctors stop using body mass index (BMI) just as a way to evaluate well-being.
The decision to move away from trust controversial height-to-weight ratio due in part to the fact that the original data collected was based only on earlier generations of non-Hispanic white populations.
In a statement, the AMA said it “recognizes that relative differences in body shape and composition across race/ethnicity, sex, gender, and age are essential considerations when using BMI as a measure of adiposity, and that BMI should not be used as the sole basis for denying appropriate insurance benefits .”
Instead, the AMA suggests that BMI should be used in conjunction with other tools to measure obesity, such as “measures of visceral fat, body fat index, body composition, relative fat mass, waist circumference, and genetic/metabolic factors.”
Why is there a discussion?
At the individual level, BMI has several disadvantages. But it can be a good tool for tracking rising or falling obesity in the population.
One of the reasons people like BMI is that simplicity: To estimate BMI, you take your weight in kilograms and divide it by the square of your height in meters. Those with a BMI of 25 to 29.9 are considered overweight, while those over 30 are classified as obese.
However, the simplicity of this formula also makes it problematic for evaluating individuals. BMI does not take muscle vs. fat into account. For example, an athlete may have a low body fat percentage, but a high BMI due to muscle.
When it comes to health, it may also matter more where you’re carrying fat, which BMI can’t tell you. For example, there has been belly fat associated with high blood pressuretype 2 diabetes and heart disease.
It is also possible that your BMI is higher than average and you are generally healthy called metabolically benign obesity. This may be due, at least in part, to how different bodies react to fat. Different races and ethnic groups can also carry and hold weight differently.
There is also an important economic reason why BMI should not be a marker of weight and health. Insurance companies may not cover treatment costs for people who do not belong to the BMI category. For example, in May 2021 The Washington Post reported that a black woman with an eating disorder had a BMI that was too high for her insurance to cover treatment. He had to pay $800 out of pocket a month.
The tool may also underestimate the number of obese people. A new study presented at the annual meeting of the Endocrine Society suggests that BMI ignores cases of obesity while obesity is determined by the percentage of fat and muscle.
Perspectives
BMI is an imperfect tool, but one of our few screening options
“Right now, our best tool that’s readily available in all clinics is going to be BMI-based screening. We need better things. (AMA’s policy) is a push in the right direction, but we also have to accept the reality of what we have right now.” – obesity doctor Carolynn Francavilla Brown, STAT news
Focusing on body mass index can damage the relationship between doctors and patients
“A clinician’s focus on BMI can lead to unproductive weight-related discussions that break the doctor-patient relationship and can create mistrust. This can lead to patients choosing not to follow their doctor’s advice, even if the advice is not weight-focused, and not continuing treatment due to shaky trust.” , which is an integral part of effective physician-patient relationships. In addition, incorrect BMI assessments can unnecessarily divert the clinician’s attention to weight, which is an easily assumed but often misleading explanation for a variety of signs and symptoms, and can lead to missed diagnoses, sometimes with serious consequences. – S. Bryn Austin, professor of social and behavioral sciences at Harvard’s TH Chan School of Public Health, and Dr. Tracy K. Richmond, assistant professor of pediatrics at Harvard Medical School, MedPage today
BMI may be more accurate than we assume in detecting excess fat
“Despite its limitations and notorious counterexamples, BMI is strongly associated with body fat, correctly classifying people as overweight 80 percent of the time. Simple additional measurements, such as waist circumference, can be even more informative because they provide information on body fat distribution.” — Kevin D. Hall, senior researcher at the National Institute of Diabetes and Digestive and Kidney Diseases, The Washington Post
Waist-to-hip ratio can estimate where more dangerous fat is better than BMI
“A person’s waist-to-hip ratio is by far a better tool to use than BMI because it takes into account the area where fat is most likely to be problematic – the waist. “When we carry fat (body fat) in our midsection, it…
