I wrote a paper that discussed why body mass index wasn’t an accurate measurement of anything.
To get an idea of why I feel this way, let’s use some professional athletes to illustrate why BMI is not an accurate measurement of obesity:
This is a link to the roster of the Tampa Bay Lightning, a professional hockey team made up of athletes from all over the world, most of whom are also on their country’s respective Olympic teams. They are provided, as part of the team, with a full time nutritionist, the best medical care available, and they each work out 6-8 hours a day, every day. In other words, they are in the 99.9th percentile of health and fitness. According to Body Mass Index, every one of them has a BMI higher than 25, meaning that all of them are overweight.
In science, if you can prove that a hypothesis isn’t always correct, then it must be rewritten or discarded. BMI isn’t correct.
Now the American Medical Association now agrees that BMI isn’t accurate. Not because of its inherent issues, but now because they claim it is racist.
14 Comments
oldvet50 · June 21, 2023 at 6:17 am
The same could also be said about weight. Just because you are a certain height does not mean you should weigh a particular amount to be healthy. Most people say they want to lose weight but they really should lose girth! Fat takes up 125% of the space that muscle does. A pound of muscle weighs the same as a pound of fat, but a cup of fat weighs 20% less than a cup of muscle weighs.
EN2 SS · June 21, 2023 at 6:42 am
Excuse me, but your idea of science and leftists practice of science are so far apart, the Hubble can’t see from one to the other. Maybe the Webb can, I’ll check and get back to you.
SiG · June 21, 2023 at 7:15 am
Before BMI, everyone lived by the Met Life Insurance height/weight tables. Those were eventually dumped for a handful of reasons and replaced by BMI. The immediately obvious problem was that BMI had only two inputs, height and weight, which were exactly what the Met Life tables were based on. They’re both just a completely arbitrary way of saying “that person looks slim for their size.”
So if all that goes into an equation are those, how do you get anything more meaningful out of it? Is it more scientific because it uses division or because you divide weight by height squared?
Body composition scales aren’t accurate enough for lab quality work, but neither is BMI (or the old tables). A scale that’ll tell you % body fat is around 20 bucks. It’s a more valuable number than BMI.
WallPhone · June 21, 2023 at 1:18 pm
Exactly this.
BMI is a ratio of related measurements, and thus has more value than height or weight alone.
In the same vein, the power to weight ratio for sports cars and the price to earnings ratio for stocks are both better predictors of actual performance than their source measures, but are still imperfect measures of actual performance, which is a sum of many more variables than two.
Height and weight are easily measured. The cost of getting the to the end value of a perfect theoretical formula rises exponentially as you add in the measures that contribute iotas of difference against the majority of the samples measured.
Pretty soon you’re in the realm of climate “science” models where you simply forgot to account for thermal transfer from the Earth’s core.
Bad Dancer · June 21, 2023 at 7:57 am
Aye its a nuanced issue and their pants on head denial of health is going to be a pain.
My brother was in the Navy when they were still doing neck and waist measurements to calculate BMI and was constantly marked as overweight. Didn’t matter that he smoked many of the “Fit” skinny guys at PT or that his neck looked like a bulls. Dude was hardly fat he was just a big ol bama boy. All that head shed saw was a sailor constantly rated as overweight gee he must be a dirtbag pass him over for promotion.
exile1981 · June 21, 2023 at 8:07 am
I was always taught bmi index falls apart at the two ends of the spectrum, very small people and atheletes. Insurance companies live it as it gives them a medical justification to charge more for some people.
The AMA has lost all credibility these days, just another far left group advicating for societal collapse oretending to be a professional association. No different than teachers association (and unions) or even engineering association lately.
Grumpy51 · June 21, 2023 at 9:31 am
The “old” concept (1997) of BMI and obesity had more to do with risk of 5 medical issues – increased risk of stroke, high blood pressure, diabetes, cancer, and heart attack.
It did NOT take into account cardiovascular fitness.
When one takes the text out of context, one is left with a con.
Some Guy · June 21, 2023 at 9:54 am
I thought that BMI was to be used roughly as a person’s metabolic condition; i.e. if someone shows up with a BMI of 23, but clearly has noodelly arms and a pooch, a doctor still looks at them as metabolically compromised. Conversely, if a guy shows up with a BMI of 32 but is clearly fit, he will be tested otherwise.
BMI as a shorthand to metabolic health.
Divemedic · June 21, 2023 at 9:59 am
Unfortunately, that isn’t how it’s actually been used
Some Guy · June 21, 2023 at 10:20 am
Sounds like misuse of a tool rather than the tool being broken.
Big Country · June 21, 2023 at 10:33 am
DM, you’ve seen me… and I was out-of-shape when we met, but back in the day? I am, as of back in 2014 -the only- contractor who got a weight waiver when I went to CRC. It never was given out. They had me as Grossly Deadly Morbidly Obese (think it was like a 44? BMI on what I call “The Kate Moss BMI Chart”) I threw such a shit-fit they did the Tape Test and the doc had to get a step stool to get up to measure my neck (26 inches) He was giggling ‘cos I was so big compared to him, and they took pictures as well and sent them up the chain… it came down to the CENTCOM Surgeon General (literally a two-star) who sent back an approval, and with a note “I really wouldn’t want that guy mad at me!”
Some Guy · June 21, 2023 at 11:44 am
Nevermind. I read the article. So, white guys should find Lizzo to be the epitome of sexiness, and everybody should eat all they want to and inject these super-awesome GLY-# drugs to lose weight.
Got it.
Fifty One Phantom · June 21, 2023 at 2:31 pm
Nothing is one size fits all and there are some who are “big boned” who actually wear the fat well.
Every now and then you see a fattie with a pretty face and wonder what they would look like with a normal BMI.
The A1C will be next I bet.
Saw a Clown World video of huge butt freaks on some balcony by a pool and thought that it would collapse, the name was Zuma the Butt or something and it was some serious junk in the trunk.
Only a shit ridden society would worship the azz like certain segments of this Chiquitastan.
Jonathan · June 21, 2023 at 8:27 pm
I’m curious about the motivation of the men who came up with these measurements.
I’ve read that the military fitness standards were created after WWII by a group of runners who felt theirs was the ideal body type, so the standards were intentionally set against weightlifters and others with a bigger body.
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