BMI Backlash: What the Numbers Don’t Tell You

In September 2015, Air India grounded 130 of its flight attendants. Permanently. It wasn’t because they showed up late to work, didn’t fulfill education requirements, or even performed poorly. Nope, it was all due to their BMIs.

The flight attendants who were dismissed all had a BMI, or Body Mass Index, over the measurement that was deemed ‘appropriate’and safe by the airline. Stating that, “People who are fitter can respond quicker and more efficiently in case of any untoward situation,” Air India officials unceremoniously dumped their employees—mostly women—for essentially being too fat to be flight attendants.

But (newsflash) a high BMI doesn’t mean someone is unhealthy. So why are we still using it?

The BMI standard was created by a Belgian mathematician who had zero medical training, in the mid-eighteenth century. Initially conceived as a standard of measurement, the formula is simply an individual’s body weight divided by the square of her height. An accompanying chart plots three umbrellas that a BMI can fall under: underweight, healthy, and obese.

Health is a little more complex than a number on a scale—a study published in the European Heart Journal found that after reviewing the health of 43,265 participants, the most important determinant of their health was not their weight or BMI, but their physical fitness level.  This fact, along with more and more emerging information conclusive that the foods we eat affect our health as much as  how much we exercise, have brought the BMI formula  under fire for a few important factors that it ignores while measuring health.

First, BMI calculation doesn’t take into account gender or age. Seems like an important detail to overlook, right? Women naturally carry more body fat than men, and as we age we lose muscle mass and gain fat mass. Unfortunately, the equation for BMI doesn’t look at tissue makeup in the body—it simply measures height versus weight.

The problem with that? Fat and muscle have different mass. A pound of fat takes up more area than a pound of muscle, but they weigh the same: a pound of fat is about the size of a grapefruit, but a pound of muscle is about the size of a tangerine.

If a person is more muscular, they might be “overweight” or even “obese” on the BMI scale, despite the fact that they aren’t anywhere close to it in real life. And someone who doesn’t work out has little muscle mass and a higher body fat percentage could actually measure at a healthy BMI, just because fat weighs less than muscle. BMI also totally ignores waist size, a key indicator of obesity and elevated risk of heart disease and stroke.

Relying a person’s BMI to measure their health isn’t just inaccurate, it can be potentially dangerous and expensive. Insurance companies consider a potential client’s BMI when approving them for a healthcare policy, 19 states require schools to record students’ BMIs and penalize students that measure up as “overweight”, and the U.S. military requires its recruits to fall into an approved zone on the BMI chart.

Instead of counting on an antiquated equation that doesn’t truly measure health or wellness, it would be smarter to integrate different measurement standards into our healthcare. Total body fat percentage is a pretty simple and inexpensive measurement—a pair of body fat measuring calipers or a body fat scale both work—and instantly discern whether someone is fit or needs to lose body fat. As mentioned, waist size measurement is an easy way to tell if someone is at risk for heart disease or stroke. Even measuring blood pressure and blood sugar levels could be a more accurate gauge of health.

After all, health living isn’t about the number on the scale—it’s about balance, eating well, moving your body, and enjoying your life!

Illustration by Foley Wu