We rely on medical professionals to help us in our journey of taking care of our bodies and our health, but some continue to use outdated measurements to our detriment.
The body mass index, created by Lambert Adolphe Jacques Quetelet in the 19th century, has been used by doctors to determine if someone is obese for decades. It is even being used to determine obesity in relation to COVID-19 vaccine eligibility, despite the creator himself saying it should not be used to indicate someone’s fatness. Quetelet was a mathematician and not a doctor, yet many medical professionals still rely on it.
BMI is someone’s weight divided by the square of their height. This simple formula lacks a lot of nuance and doesn’t take into account the weight added by muscle and strong bones, according to NPR. It also leaves out different fat distributions for those assigned female at birth, including the added weight of breasts. For example, Olympic weightlifters would often be classified as obese under the BMI system. These oversights make BMI alone a drastically inaccurate indicator of health.
Using BMI to label someone as obese is like calling a rectangle a square. Someone who is obese will have a high BMI, but not everyone with a high BMI is actually obese.
Insurance and diet companies also have a history of lobbying for and abusing the BMI system. In 1998, the obesity threshold was lowered from 27.8 to 25 due to consulting with an organization funded by Weight Watchers International, according to Mother Jones. This caused millions of Americans to suddenly be classified as fat at the behest of diet companies. People with higher BMIs are also more likely to pay higher insurance premiums according to NPR.
BMI also further enables the fatphobia of the medical field. Numerous fat people have experienced doctors dismissing health concerns by attributing it to their weight. With BMI being such a simple formula, it makes it easier for a doctor to tell a patient to lose weight and lower their BMI rather than trying to treat the patient’s concerns.
Fatness also isn’t inherently bad or unhealthy. One’s activity level is a better indicator of their health than their weight. Regardless whether someone is fat or skinny, they’re going to be out of shape if they live a predominantly sedentary lifestyle. There are people like singer-songwriter Lizzo who are fat and work out regularly and are likely more healthy than someone who sits around all day.
The misguidance of BMI impacts the entire medical field and lowers the quality of care individuals get. Doctors need to use more scientific ways to determine a patient’s bodily health rather than taking the easier option. Individual bodies can’t be reduced down to a mathematical formula and their medical care should reflect that by being tailored to them.