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Can We Get Rid of BMI Yet?

BMI = weight in pounds/(height in inches x height in inches) x 703 = nonsense?


Does this toddler look obese to you?  According to BMI, he is….

Healthcare has improved by leaps and bounds in the past 200 years…so why are we still using a flawed equation created by a mathematician (read: not a doctor) 200 years ago to assess fitness?

I always felt slimy using it to assess clients during my early days working as a personal trainer in big box gyms.  My bosses liked it because it sold more personal training.  Numbers hit people where it hurts.  And boy does this equation hurt.

BMI was originally created to quickly and easily measure the degree of obesity in the general population.  It was never meant to be used to gauge individual health, but rather to help the government skillfully distribute resources.  Moreover, it completely neglects things like waist size and physiological make up.  In fact, people who have a very high muscle to fat ratio often come out in the overweight or even obese range (think football players and really buff movie stars).  Yes, having good bone mass and an extremely lean body can actually be detrimental to ones BMI score.

Even though I have been aware of its flaws for some time now, selfishly I kind of liked getting mine taken because it labels me as “ideal” (a girl can dream, can’t she?)  Regardless of the fact that I am in fairly decent shape, I can’t take all the credit for my good BMI score.  I do better because I am short.

The BMI equation exaggerates thinness in short people and fatness in tall people.  The equations divides weight by too much in short people and too little in tall people.  Never being personally offended by BMI, I was able to keep my distaste for it under the radar.  Flash forward T’s recent yearly physical when things became personal.

T is tall for his age and solid as a rock.  On his most recent appointment, he was put in the obese category.  In children, BMI is adjusted for age.  Big-for-their-age children often measure obese, even if they appear to have little to no excess body fat.  In other words, a 3 year old who scores obese could be the exact same size as a 5 year old who measures as normal.  If all children grew at the exact same rate this might make more sense.  But they don’t.

I do not mean to fat shame here.  Contrary to every message society tells us about body size, being “overweight” is not wrong or bad .  Smaller body size does not necessarily coordinate with better health.  I do believe that randomly comparing children, especially using an equation that is only somewhat accurate for only about two thirds of the population, is wrong.

BMI was created with a sedentary population in mind.  Thus, low muscle mass and a relatively high fat mass is expected.  Fit people tend to be dense (sometimes meathead dense, but in this case solid as a rock dense…) and dense people have higher BMI scores.  Additionally, it was never intended for use on women.

It pains me to see my son labeled, albeit incorrectly, at such an early age.  I was a chunky kid, but at least I got to remain blissfully unaware of what was “wrong” with my body until age 8.  Between taunts from my peers to comments from a well meaning dance teacher, I got the picture even without the numbers.

So now, in addition to the cruelty kids can inflict upon each other,  we have an inaccurate equation to make them feel crummy about themselves even if their body is healthy.  And the shame can begin at age 2.

If BMI is so flawed, why has it become the gold standard in health assessments?  One word: convenience.  It is much easier and cheaper for doctors and insurance companies to run some numbers through a faulty equation than it is to test for body composition.  In the case of insurance, they also get to charge healthy people who get labeled incorrectly higher rates.  If it ain’t broke….

But it is.  BMI is calculated by dividing ones weight by the square of their height.  It presumes that we get wider as we get taller, but does not account for thickness back to front.  It is a two dimensional equation being used to measure 3 dimensional people.  Geez, I guess I should have given birth to a cardboard cutout?

Going a step further, people are meant to be different shapes and sizes.  Though true obesity (extremely high fat mass) may put one at greater risk for chronic disease, it is simply not true that those with objectively larger bodies are less healthy than those with objectively smaller ones.  True health is extremely individual.

At the age of 12 I realized that eating little to nothing made me skinnier.  It was the age of diet “food”, so naturally I eschewed nutrients for chemicals with little to no calories.  Did it make me any healthier?  Not by a long shot.  My digestion was a mess.  I passed out in school.  I felt anxious and depressed.  Worse yet, I didn’t get the accolades I hoped for.  Instead of praising me for my progress, teachers gave me worried looks.  The kids I hoped to impress simply changed their taunts from “fat refrigerator” to “anorexic bitch”. (I shuddered as I wrote that, kids can be so mean!  Don’t worry, I am a grown woman now and have recovered…mostly….).  It seemed I couldn’t win.

Becoming a parent has once again made me like Goldilocks, still searching for the perfect middle ground.   Due to my previous pregnancy outcome, T was taken out two weeks early.  Each time we took him to the doctor during that first year he measured too small.  At one point they labeled him “failure to thrive” (if only I could have met whoever came up with that gem of a phrase in a dark alley, hormonal and ready to rumble….).  It seemed odd because he was, in every other way aside from his small stature, positively thriving.  I couldn’t help but wonder if part of the problem was measuring T against babies who went full term (i.e. not taken out two weeks early against their will…)  Couldn’t we at least give the kid a little time to adjust?

Flash forward to present day where he holds steady at the top of both the height and weight charts.  To the naked eye, my boy is lean and strong.  According to BMI, his size is a problem.

As we left the doctors office, J and I had a good chuckle.  Seems we just can’t get this kid to be the right size!   After laughing, I started questioning (and ruminating, but if you have read my Mindfulness Monday posts you know I’m working on that….).

How much better would life be for us and our children if we stopped worrying about where we fit in on a chart?  How would society improve if we focused less on becoming like everyone else and more on being the best version of ourselves, whatever that looks like?

True health is far from two dimensional.  I hope to teach T to love his body along with his ABCs and 123s.  He is active, enjoys copious amounts of fruits and veggies, and, more importantly, is happy.   Biased as I may be, I do believe he is perfect as he is and refuse to let a bunk equation tell either of us any differently.

Mama bear out…….

Just a typical morning of rock throwing, powered by plants….

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