I think your BMI is bullshit

I saw a pair of young girls last week at the gym reading the BMI chart kindly posted on our gym bullletin board by someone, I assume trying to be helpful.


When I look at the BMI chart, even as an educated woman, and personal trainer, I read that at 5 foot 3, barely, and 130 lbs, sometimes 135, I am right on the cusp of OVERWEIGHT, and I walk away feeling like crap about myself.

I by no means think that I am walking around show ready or at my leanest but what I DO KNOW, is that I am strong, with muscle and am NOT OVERWEIGHT.

I have never followed or even suggested a client look at a BMI chart, so having it up has bothered me for a while and until the other day I have said nothing.

BMI stands for Body Mass Index was developed almost 200 years ago by Belgain mathematician  Lambert Adolphe Jacques Quetelet. NOT a physician, just someone who was good at math, so how it has been thought to relate to bodyfat in this day and age seems ridiculous.

To get the formula, He adjusted the numbers until it fit….Quetelet had to square the height to get a formula that matched the overall data THERE IS NO PHYSIOLOGICAL REASON TO DO THIS.
The formula also completely ignores waist size, which is a clear indicator of obesity level.

The formula doesn’t take into account proportions of bone, muscle and fat in the body. Keep in mind that bone is denser than muscle and twice as dense as fat, so a person with strong bones, good muscle tone and low fat will have a high BMI. Insert myself and a whack of other athletes and fit, health-conscious people who work out a lot finding themselves classified as overweight or even obese….PLEASE

I stole this from a website today so can’t take credit for it but it hits the nail ON THE HEAD!!!


“The CDC says on its Web site that “the BMI is a reliable indicator of body fatness for people.” This is a fundamental error of logic. For example, if I tell you my birthday present is a bicycle, you can conclude that my present has wheels. That’s correct logic. But it does not work the other way round. If I tell you my birthday present has wheels, you cannot conclude I got a bicycle. I could have received a car. Because of how Quetelet came up with it, if a person is fat or obese, he or she will have a high BMI. But as with my birthday present, it doesn’t work the other way round. A high BMI does not mean an individual is even overweight, let alone obese. It could mean the person is fit and healthy, with very little fat.

Because the majority of people today (and in Quetelet’s time) lead fairly sedentary lives and are not particularly active, the formula tacitly assumes low muscle mass and high relative fat content. It applies moderately well when applied to such people because it was formulated by focusing on them. But it gives exactly the wrong answer for a large and significant section of the population, namely the lean, fit and healthy. Quetelet is also the person who came up with the idea of “the average man.” That’s a useful concept, but if you try to apply it to any one person, you come up with the absurdity of a person with 2.4 children. Averages measure entire populations and often don’t apply to individuals.”


Not only do Insurance companies still use this tracking, and charging MORE for covereage of those of us inteh “danger zones” of the BMI (even if you are super jacked and NOT obese), Doctors are also using this formula, because it’s easy, accurate or not.

The worst part in my opinion is what I witnessed  last week. The two girls who walked in cheery, young, innocent, happy and full of life, walked out 2 minutes later with their heads physically down,smiles no longer visible, and a slowness in their stride asking each other if they are actually overweight.

These beautiful girls were NOT overweight, they were preteens and athletic and full of life, and I watched them deflate before my eyes because of some stupid piece of paper with numbers on it written 200 years ago….


Train well, eat well, celebrate yourself everyday.