Why Everyone Should Ignore BMI As A Health Marker

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A new study shows that the Body Mass Index (BMI) is truly crap! More than 54 million Americans classified as overweight or obese are actually healthy. Yet millions of thin people are wrongly labeled as healthy. Image courtesy of FreeDigitalPhoto.net and Mister GC.

A new, major study was just released that actually tested the accuracy of BMI against a range of cardiometabolic health markers. Thanks to our government’s reliance on BMI, more than 54 million Americans classified as either overweight or obese by BMI standards are in fact healthy.

This is huge, as our friends in Washington are looking to use BMI to increase healthcare costs even higher.

My BMI Number Vs. My Doctor
According to my doctor, I’m perfectly healthy. In fact, at my last physical, he didn’t see a need for me to lose more weight. I weighed 185 pounds and he felt any additional pounds I wanted to shed were purely for vanity. As far as he was concerned, my health numbers were awesome.

Why the clean bill of health when I weighed 185? My blood pressure was low but normal for more than a year. My triglycerides were low as was my fasting insulin level. And my HDL rose while my LDL dropped. My waist was clearly smaller than my hips, a physical telltale sign that I was no longer a candidate for heart attack or diabetes. Plus, in just over 3 years I’d dropped 145 pounds and kept it off. Woohoo!

But despite the good news, the federal government and my health insurance don’t share this opinion about my hard work to get healthy. You see, my Body Mass Index (BMI) is slightly under 30. But “normal” BMI is between 18.5 and 25. So I am considered overweight and not healthy because of this number.

But how can that be? My health numbers tell me one thing, yet my health insurance carrier and the federal government say another.

So who is right? The man who has the medical degree? And who’s been my doctor for 10 years and carefully measured my transformation over the last 4 years? Or the “experts” employed by health insurance companies and the federal government who never met me, don’t have the foggiest idea about my lifestyle, don’t see patients, and who apply a single metric to measure health because it is easy?

How Is BMI Calculated?
How easy is BMI to measure? Here’s the formula:

BMI = (weight in pounds x 703) / (your height in inches x your height in inches)
Dot’s BMI (at my last physical) = (185 pounds x 703)/(66 inches x 66 inches) = 29.86

Simple formula…but for the life of me I can’t figure out why I multiply my height by…my height? And if BMI calculates my percentage of body fat, how does it take into account my muscle mass? Or my bone density? Also, I thought the location of where we accumulate fat is important too. And as a woman, I’m suppose to carry more fat than a man. So how is that accounted for?

Why BMI Is Poor Judge Of Individual Health
We need to take a look at when and who created the BMI formula.  It was created in the 1800s in Belgium by a mathematician — Lambert Adolphe Jacques Quetelet.

Let that sink in for a moment. The BMI formula was created by a mathematician. Not a doctor. Not someone who actually had experience with human biology, chemistry or physiology. Nope. Someone who could do math. 

He wanted to create a quick and easy way for the government of Belgium to estimate how much of the general population was obese.

NPR has a pretty good take on why BMI is flawed, including how the formula is rigged to fit the data (the “your height in inches x your height in inches” mystery). So it’s really a math hack and not a very good one to begin with.

One of the most common flaws people point out has to do with athletes. It’s clear to anyone with half a brain that athletes in their prime (think Michael Jordon, Tom Brady, Michael Phelps) are not overweight or obese. Yet, they are if you look at their BMI numbers.

BMI is just a poor judge of body fat. The calculation doesn’t look at age, gender, muscle mass, body frame, or fat distribution. Sure, there are online calculators that do ask for you age and gender, but the BMI system doesn’t really care. To me, this is more jerry-rigging of an already flawed math formula.

Women carry more fat than men. Men have more muscle mass than women. We all loose muscle mass as we get older. In other words, our bodies, which change with aging, are incredibly difficult to peg down so simply.

Another problem: BMI can’t tell the difference between subcutaneous fat (under your skin) and visceral fat (around and in the organs). Visceral fat is dangerous to our health and one of the best indicators of heart disease, stroke and other metabolic diseases.

Just because someone looks thin doesn’t mean they don’t have high levels of visceral fat. The medical community is well aware of “skinny fat” – thin people who look healthy but have out of control blood sugar, high LDL and triglyceride levels, high blood pressure, and lots of visceral fat.

Yet, those who worship at the alter of BMI think these “skinny” people are the picture of health. And if your doctor relies on BMI too much, then I’d say find a new one fast. Because it means he/she isn’t looking at the best indicators of your true health.

Why BMI Matters To You (& Your Pocketbook)
Guess which health metric insurance companies use when determining what to charge for health policies? BMI. It does make me wonder if insurance companies want to keep using BMI to keep premiums high.

Think your premiums are high now? Just wait. A new rule proposal by the Equal Employment Opportunity Commission (EEOC) looks to penalize people with BMIs higher than 25. Yep, our federal government is looking to wrongly penalize more than 54 million healthy people because their BMI is more than 25.

And if they are unfairly penalizing one group, another group will be unjustly rewarded with low premiums. You guessed it: the “skinny fat” folks who have undiagnosed pre-diabetes, metabolic syndrome, and/or high visceral fat get rewarded.

The government bean counters think if your premiums increase because of your BMI level, that extra cost will “shame” “nudge” you to lose weight.

Keep in mind that these are the same folks who think the ONLY way to lose weight is by eating less (so that you feel hungry all the time) and exercising more (which stimulates appetite). And of course they expect you to lose weight while eating the low fat diet (which doesn’t work) they’ve nudged us into for more than 50 years. All this, while accurate health markers like blood pressure, HDL, triglyceride, and fasting insulin levels are completely ignored.

I’ll leave you with some words of wisdom from my doctor when I asked him about my BMI level:

“BMI is crap.”

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