Comment by FeteCommuniste
4 hours ago
> The most notorious of which is BMI; it is practically a category error to infer someone's health or risk by individual BMI, and yet doing so remains widespread amongst people that are supposed to know better.
BMI works fine for people who aren't very muscular, which is the great majority of people. Waist to height ratio might be more informative for people with higher muscle mass.
My understanding is that it doesnt even do that, because it creates false negatives for the so called skinny fat body type: significant visceral fat mass, which is what we are concerned about, but not much muscle or peripheral fat mass, thereby not being flagged by BMI screens, even though they are at risk.
As a person who has been told I'm "morbidly obese" for decades now, I will say that doctors at almost every level look at your chart not you. I've been told time and time again that until I get my weight under control, my health will suffer.
I'm 5'8" and weigh on average 210lbs. My BMI isn't even morbidly obese, it is 31, which is just "regular" obese, but on top of that, a DEXA scan shows that I am actually only 25% body fat, with only 1lb of visceral fat.
Doctor's don't care about that, they see on the Epic chart that my BMI is > 30 and have to tell me some spiel about a healthier lifestyle so they check check off a checkbox and continue to the next screen.
> Doctor's don't care about that
Literally all of them?
When humans talk, they use generalizations (and don't need to annouce them). Here it means that most doctors don't care about that.
Follow that rule next time you read such a statement in a context that's not formal math.
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I can't say literally all, but in my experience with having to get a new GP almost every year because of health insurance changes, location changes, hospital consolidation buying my GPs practice, and multiple doctors retiring or just quitting medicine (my last GP was tired of medicine after practicing for only 3 years). Over the last 20 years, I've had almost 15 GPs across 5 states (NY, NJ, CT, TX, LA). I also have multiple auto immune diseases, so I have had a handful of specialists of various flavors (endocrine, oncology - not for cancer, cardiology, and urology), but only need them occasionally.
Almost every single start of every single appointment (including a follow up from just a couple days prior), they comment about my BMI. It is the rare time they don't that I remember. My last urology appointment the doctor was very congenial, didn't even go over the lab work, just said, everything is looking good, asked how I was feeling, everything good, alright, refilled my prescriptions and left.
I dunno, basing life decisions off a metric that has a fudge factor built into it to make the regression work feels sub-optimal to me.
BMI underestimates in most cases and your body fat is higher then the chart would predict.
When people say "oh BMI isn't accurate" it means you are more overweight then it suggests unless you are literally an extreme body builder.