The Body Mass Index is Pointless Unscientific Garbage

Yeah, that got your attention, didn’t it? A Texas hospital is refusing to hire staff over a certain BMI threshold. I'm telling you why this is a dumb idea.

Apr 11, 2012 at 3:00pm | Leave a comment

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Succumbing to the deadly BMI scourge.

 A Texas medical center is in the news at present for a controversial hiring policy: Citizens Medical Center has decided to summarily reject all employment applications from anyone with a BMI of 35 or higher.

If it were simply a matter of health concerns or lowering insurance premiums, this policy would be irritating enough -- but the decision is based explicitly on employees’ appearance. The change has been in effect for over a year, but is now under fire owing to a lawsuit being brought against the employer for discrimination.

[The policy] states that an employee’s physique “should fit with a representational image or specific mental projection of the job of a healthcare professional,” including an appearance “free from distraction” for hospital patients.

“The majority of our patients are over 65, and they have expectations that cannot be ignored in terms of personal appearance,” hospital chief executive David Brown said in an interview. “We have the ability as an employer to characterize our process and to have a policy that says what’s best for our business and for our patients.”

Fact is, it's perfectly legal to discriminate against job applicants based on their weight in most of the US; only Michigan has a statewide law banning the practice, and six individual US cities prohibit this as well. Historically this sort of decision has been left to the employer on the basis that weight may physically impair a person from successfully doing the job as required, and the employer would make that determination of ability better than any government body.

The Texas case is different, because the medical center has dared not to pin its concerns on ability but on appearance -- simply put, according to the text of the policy itself, they do not want to hire fat people mainly because of how they look. The hospital administration has since begun to backpedal a bit, and argue that the policy is ALSO a matter of keeping their own health care costs down. And yet,

[A doctor at Citizens who declined to be named] said body mass index as a primary measure of obesity is not a good indicator: A professional football player might have a body mass index of 32, which is technically obese, but only have 7 percent body fat.

And unless obese job applicants have other precipitating health factors, he said, their weight wouldn’t get in the way of being a successful hospital employee. “If more people knew about it,” the doctor said of the employment policy, “they would be justifiably pissed.” 

 The prospect of a hospital requiring job applicants to disclose private medical information (which is what the BMI is) seems laughable, and is itself probably against the law, even if bias against the hypothetically-unattractive would-be employees isn’t. But having read all the handwringing over the unfairness of a policy against hiring people who don’t look the “right” way, I think it's important to note that the BMI itself is a deeply flawed measurement of size, ability and health.

The Body Mass Index we know today has its origins in the mid-1800s, when Belgian statistician and “social physicist” Adolphe Quetelet devised it as a part of his efforts to describe the “normal man” of his era, both physically and socially. The original Quetelet index had nothing to do with health or obesity, but was merely a means of working out the average build of a typical male human. 

Enter Louis I. Dublin, who over one hundred years later would oversee the development of height and weight tables in his capacity as vice president of Metropolitan Life Insurance Company. These tables -- familiar to those of us who grew up prior to the government adoption of BMI -- were based not on medical information but on actuarial statistics. Basically, the charts depicted the mortality rates of men based on height and weight, which was important information to an insurance company for rating life insurance policies (as knowing who is likely to “collect” -- i.e., die -- sooner is useful for running a business whose purpose is to pays out upon the death of the insured).

Both of these developments, upon which our modern Body Mass Index is based, were designed to assess mortality trends over large populations, not to predict health or wellness for individual patients. 

Next, in 1972, obesity researcher Ancel Keys was working to come up with the best height/weight formula to predict body fat percentage. He landed on Quetelet’s formula -- “the weight increases as the square of the height” -- as the most accurate gauge, and it was renamed the Body Mass Index.  

Keys, however, only intended this measurement to be used in epidemiological studies -- that is, studies across broad and diverse populations to show overarching trends. Indeed, Keys himself explicitly stated that the BMI he designed was inappropriate for individual diagnosis, as it purposely disregarded the diverse characteristics that affect how weight impacts a unique person. The very thing that made the BMI an effective measurement for epidemiologists -- its failure to account for age, gender, race, and build, among other distinguishing factors within a population -- made it not applicable to the health of a specific patient.

Prior to this point, the determinations of “normal” body size made by doctors were governed not by medical data, but by insurance companies looking exclusively at mortality rates with no controls for any other extenuating factors.  So what happened next? In 1985, the National Institutes of Health adopted the BMI as an individual standard for obesity, of course. Not because it was the best choice for this measurement, but simply because it was EASY. Compared with other methods of determining body fat percentage -- most of which require an individual’s body to be assessed -- the BMI was a straight-up math problem that served up an answer in seconds, without any need for pesky interpretation.

The original BMI cutoffs for obesity were 27.8 for men and 27.3 for women, and there was no “overweight” category. But the National Institutes of Health wasn’t done yet! If it wasn’t enough that the NIH had adopted a formula never intended for individual diagnosis, in 1998 they doubled down and eliminated the half-assed gender distinction. They created “overweight” as a category literally overnight. And they pushed back the BMI standards to 25 for the newly overweight folks, and 30 for the obese.

These changes were actually quite controversial at the time, with many researchers believing them to be unnecessarily alarmist. 

 The outcome of the changes was that 25 million Americans went to bed one night having normal bodies, and woke up the next day fat -- all without having gained an ounce.

Unsurprisingly, criticism of the BMI is growing, as more researchers and doctors realize that sometimes the simplest approach taking the least effort is not always the one that leads to their patients’ best health. Some medical researchers have argued that the “obesity epidemic” itself is a myth, bolstered by a 2005 study published in the Journal of the American Medical Association by a researcher at the Centers for Disease Control which found that “overweight” people have lower mortality rates than “normal” weight people, according to the BMI standards. Also, there is a long history of allegations of data being skewed in favor of fat hysteria because an obesity epidemic is a profitable model for diet companies and drug manufacturers.

It’s hard to make a strong case in favor of the BMI at this point, except to assert that it's really easy to use. And that's the only thing it has going for it: It sacrifices accuracy for simplicity. The BMI, after all, even ignores contributing factors like body fat percentage and distribution, and the size of an individual’s skeletal frame; factors like these can result in the so-called “skinny fat,” people who rank as normal on the BMI scale, but because of their smaller frame, high fat percentage, and/or relatively low amount of muscle tissue, may be at higher risk of allegedly obesity-related diseases than people who rank as “obese” (note that a significant number of professional athletes -- as well as many folks who just lift weights or do Crossfit -- qualify as “overweight” or “obese” owing to the BMI’s lack of accounting for what their body mass is made of).

Officials have stated that the no-fatties policy of the aforementioned Texas hospital is rooted in the idea that healthcare practitioners should look, well, healthy, not by some arbitrary personal standard (which, apparently, would be offensive), but by a dubious measurement that was never intended to be used on an individual, and which truly tells us less than nothing about their overall physical well-being.

Utlimately it doesn't matter, as the BMI doesn't predict an attractive appearance any more than it predicts a healthy body. The Citizens Medical Center policy employs the BMI precisely because it lends their gross decision-making process an air of scientific legitimacy, and many people who have followed this story have cheerfully fallen for that sham because they believe the BMI has value. 

But what if it doesn’t? What if this Texas hospital is flat-out treating the employment of doctors and nurses like hiring waitresses at Hooters? You have the look, you get the job. Call me foolish, but I’m more interested in medical care that is smart, thoughtful and professional, and if I can get all of that, I couldn’t care less about how well my doctor fills out his scrubs. Or, for that matter, whether he fits into a certain weight slot for his height. 

It may surprise you to learn that Lesley enjoys being told how irresponsible she is for advocating in favor of self-acceptance, holistic well-being, and subjective definitions of health for every single individual on the planet. Indeed, she keeps a Twitter for this very purpose.