The Great BMI Debate

Is the Body Mass Index a helpful health calculator – or is it fatally flawed? Today we investigate an old standard that’s recently come under fire.


Throughout history, science has delivered all sorts of equations for determining whether or not our bodyfat is at healthy levels.

At times this question has been answered by our total weight, regardless of muscle, fat or water ratios. At others, we’ve furrowed our brows as we grabbed our waists to find out whether we could pinch an inch.

And then one day, the BMI – or Body Mass Index – came on the scene. We haven’t looked back since, but how accurate is the BMI, really?

In recent years, the BMI has come under fire as potentially flawed. As the argument continues among the medical community, at dinner tables and on heated, passionately-worded blogs, the public is left to wonder: is the BMI accurate? Should we be using it at all?

The History of the BMI

The occasionally controversial Ancel Keys brought the BMI formula into the mainstream.

Although we think of the BMI as a late-20th century feature, it was actually conceived by Belgian astronomer and mathematician Adolphe Quedelet between 1830 and 1850. During this time, Quedelet, whose specialties were morphing into statistics and then sociology, devised the idea of human body weight squared to height as a mass ratio.

Nevertheless, it wasn’t until a 1972 paper published by the late Ancel Keys in the Journal of of Chronic Diseases that the ratio was named the BMI. After that time, the word came more and more frequently into common usage, until it replaced total weight as a weight-related health indicator.

Since the start the BMI has been only half-embraced as adequate – even by its founders.

Interestingly, Keys himself was unwilling to commit to the BMI as fully accurate, calling the formula a “…not fully satisfactory” method but rather dubiously stating that it was “at least as good as any other relative weight index as an indicator of relative obesity.”

Nevertheless, the BMI became the gold standard of health as regards weight as, mass or no mass and formula or no formula, we still utilize it to indicate obesity or lack thereof – in other words, an underfat, healthy fat or over-fat condition.


Science, Criticism, and the Blogosphere

Scientists, bloggers and laypeople have been doing their own research, both online and analog, in search of the perfect bodyfat and fitness formula.

Partially due to the explosion of the internet – and in particular, of both personal and scientific blogs – the BMI, like hundreds of other medical and scientific indicators, came under a more concentrated criticism after the turn of the 21st century.

Unlike in times past, the internet has now given us a collected massive resource to argue, debate, research and for the more careful and methodical, review actual peer-reviewed published studies as we wade through a sea of information in search of the truth.

It’s possible to be very fit yet show up as overweight or even obese using the BMI formula, critics say.

Bloggers in particular who have a foot in the health-and-science door argue spar routinely (and hotly) over whether the BMI is helpful, a partial indicator, or whether it should be tossed out the door entirely for something new.

Unfortunately, the BMI can’t tell whether a given individual is healthier at a leaner or plumper state, and may be thrown off by a whole host of factors. For example, it’s possible to be very low on body fat and be and very built up muscularly, yet show up overweight by BMI, critics of the formula argue.

Conversely, with the weight v. height formula as assumed mass, a person could be very thin but have low muscle tone and actually have too much bodyfat than is good for him or her, critics argue.


A Middle Ground…and A Holding Pattern

Gauge your fitness not only by the BMI but how you feel and how well you perform, experts advise.

Meanwhile, larger scientific and academic collectives remain conservative. They point out that although it’s not perfect, the BMI does usually come closer to an accurate bodyfat ratio than simply weighing oneself on a scale (which will only show total weight, not how much is fat and how much is muscle, bones, organs and blood).

As scientists and dabblers alike rush to the finish line of a better fat and health indicator, most take the stance that the BMI can at least deliver an approximation of health. Others argue passionately that allowing the BMI to remain the global standard means healthy people may miss out on or pay more for insurance premiums while other, less healthy individuals with higher overall body fat as a ratio could be considered healthy simply due to one not-very-accurate number.

Amid the crossfire and potential ramifications, any individual’s best bet is to go by not only BMI but by one’s performance, alertness and feelings on a day-to-day basis. If you’re at a supposedly healthy BMI but are often tired and sluggish, experience digestive issues, rings around your eyes or have received a concerning fasting glucose or other metabolic test, it’s time to rethink your diet and lifestyle, experts say.

And if you know your diet is less than optimum, revamp it now, not after you’re already stick, according to diet and fitness professionals. You may feel fine for now, but many metabolic conditions take years or even decades to produce symptoms…and then you have a serious issue to deal with and are older to boot.

While the world waits for something more accurate than the BMI, judging how you feel, how your clothes fit, how alert you are and where your routine medical tests fall will give you your best look to date on how healthy you are and whether there are changes to make right now so you can have a healthier, fitter future.




Scroll Up