“I’m not overweight, I’m under-tall.” –Garfield
While that line was meant to evoke a smile in the 1980s, I don’t find it funny. At all.
For over a century now, physicians have used weight and height to determine what constitutes obesity. The Body Mass Index (BMI) is used by many health care professionals, and it is a load of garbage.
I want to talk about why you shouldn’t buy into the BMI myth and what you can do about it.
First, let’s back up to look at BMI and the math behind it:
BMI = kg/height (in meters)2
To keep it simple, let’s say you weight 220, or 100 kg and are 5’7”, or 1.7 meters.
100/(1.7 x 1.7) = BMI of 36.6
So in this scenario, the 220-pound woman who is 5’7” is obese.
Without telling you my weight or height, I am technically “morbidly obese.” Actually, according to the BMI chart, I would have to be 7’4” to be considered “normal” given my current weight. And this system to determine obesity is a load of crap. Why?
It belongs in a museum. It was invented over 150 years ago. What we now know as BMI was first proposed by a Belgian mathematician named Lambert-Adolphe-Jacques Quetelet. He was one of the first people to link math to explain social statistics like crime rate, suicide rate, and, you guessed it…weight.
So Quetelet came up with the mathematical formula for BMI in 1842. While it was really not a bad place to start, there’s a huge problem with it…It doesn’t take into account people live in the third dimension.
Human beings aren’t one easy math equation. We aren’t two-dimensional beings like a painting. We have curves, rolls, appendages, and we occupy space. So BMI doesn’t take into account such things as bone density or stature, which does explain the difference of BMI numbers on people who weigh the same.
BMI doesn’t distinguish between fat and muscle. So if we go back and look at the 220-pound woman who is 5’7”, there’s a big difference if she as an elite heavyweight judoka with a higher percentage of muscle than a woman who is less athletic and has a higher body fat percentage. In either case, the muscular judoka is obese the same as the less athletic woman.
How is that fair? It’s not, and that is why you need to stop worrying about BMI.
Instead of using BMI, there are other options for determining obesity such as:
- Waist-to-hip ratio
- Waist-to-height ratio
- Surface-based body shape index (which takes into account the entire body’s surface)
While it does take more work to measure muscle or fat mass than a simple math formula, I would rather subject myself to calipers than ever use BMI again.
So what do I do about it?
I talk to my doctors. My general practitioner and gynecologist know I’m fat. I know I’m fat. They know I know I’m fat. I never get on the scale when I visit the doctor because I weigh myself every week. (Seriously—refuse to get weighed at the doctor’s office.)
But I talk to both of them about my weight loss, how I can treat my PCOS symptoms (the main cause of my obesity), and they keep an eye on my blood work to ensure I am healthy. The next time I visit them, though, we are going to discuss better alternatives to measuring my health than BMI, because I am done with it.
I know I can do chores, walk, do yoga, run short distances, and enjoy what life has to offer. I’m not letting numbers on a 100-year-old chart tell me if I am healthy or not. There is a better way, and until you owe it to yourself to talk to your doctor about the BMI lie.
The next time you see a headline about Americans being obese, I encourage you to tune it out. BMI is an extremely antiquated, short-sighted way of measuring health. There are other ways to measure health, and you need to talk to your doctor about better alternatives.
Don’t let BMI trick you into thinking you are overweight/obese/morbidly obese. You are beautiful just as you are, and you are certainly more special than numbers on a chart.
Do you buy into the logic of BMI? Why or why not? Comment below!