When I was a young girl, I never had a problem questioning authority (much to my patient parent's chagrin).  Still today, you name it, no matter the subject, I always feel compelled to question and to dig deeper.  Long before there was Google, I spent many delightful hours (and still do) in bookstores and libraries.  At last count, there are about 4,000 books in my house. (Yeah, I'm a hopeless bibliophile.)

On my never-ending quest for truth, I continue to spend countless hours excavating, and diving deep into a wide variety of subjects, but especially books about ancient healing practices, modern science, fitness, and health.

One of the things that I have often questioned is the conventional wisdom around body-mass index, or BMI. While I personally gave BMI the side eye,  I thought surely our doctors and medical experts know best, right?

Well, but maybe not. When I applied the BMI theory to my grandmothers, the results were just the opposite of what you would expect.

Their lives were similar in many ways: They both came to Philadelphia during the Great Migration, they lived (and died) in the same North Philadelphia neighborhood, and they were both petite.

They both also had fiery personalities, but the most obvious difference between them was their weight.  One was lean and the other was overweight. All things being equal, if the BMI is scientifically correct, then my lean grandmother should have outlived my overweight grandmother, right?

Well, just the opposite happened. For unknown reasons, my lean grandmother died at home in her sleep at 65, but my pleasingly plump grandmother died at home in her sleep at 90. That's a whopping 25-year difference!

Sure, on the surface I can just accept the reasoning "when God say's it your time, it's your time."

On the other hand, I just kept thinking about the legitimacy and accuracy of the BMI, which dominates so much of the public and private concern and angst around weight. So, I start researching the BMI, and discovered that, low and behold, like many "medical facts," it's simply not true.

Let me break it down. The dude who created the BMI, Lambert Adolphe Jacques Quetelet, from Belgium, was not even a doctor or medical researcher, he was a 19th century mathematician.  It was originally called the Quetelet Index and he created it to measure the degree of obesity in the general Caucasian population.

That's right, when it comes to race and ethnicity, the BMI is grossly inaccurate.  The BMI typically overestimates fatness in people of African descent, and underestimates the fatness in people of Asian descent.  When you apply the BMI to athletes — you guessed it — it's usually dead wrong.

Which begs the question: Why are we following a 200-year-old medical lie? Even worse, why are physicians, insurance companies, and employers still using this fake medical fact?  I have a sneaky suspicion that our reliance on the BMI has everything to do with high profits and zero to do with health or fitness.

After all, high BMI's mean the insurance companies are justified in charging you higher premiums, and Big  Pharma makes out big time from all of the additional medications that are likely to be prescribed.  So, while I hate to be cynical, something tells me that the BMI is too big to fail — there's just too much money in it now to let it go.

Ironically, the lives of my grandmothers taught me everything I need to know about the BMI. Both of my grandmothers would agree that the BMI should be thrown on the scientific/medical scrape heap, and they would advise to never use the BMI to determine your health, fitness, nor your longevity.

In truth, my grandmothers never worried about their BMIs; they each loved, laughed, and lived on their own terms.