The intended use is to get a quick overview of populations and it works great there. For individuals the Waist to Height ratio and Waist to Hip ratios are better quick scan controls.
It’s also good as an estimate if you hugely widen what’s taken as normal. 80 is just too damn high and 12 for an adult is just too damn low.
I mean, sure, but unless the physician is blind is bmi really needed at that point? :)
Modern EMRs flag various data for review. A BMI over or under a specific range triggers a dietician consult to review the patients diet orders. Dietician doesn’t even review most patient charts without a consult, so out of the 5 things I forget to do everyday, the EMR can look at the height and weight I put in and put in the consult automatically. It’s one less thing and lemme tell ya, there are a LOT of things. So if I’m admitting a little old lady who was on the floor of her house after 2 days with a broken hip, in the middle of reconciling her medications and getting all of her feces off her, the EMR will call the dietician for me, who will look at her and be like “oh she REALLY needs some protein shakes yeah.”
It’s just a method for guestimating how much of a body is lean mass vs fat. There are a few others, such as the Navy method, that are more or less accurate for different body types
The current state of the art is DXA scanning:
Worked how?
It fully works as intended. It’s only when people try to use it for other purposes that it fails. It’s an estimation tool, nothing more or less
BMI was never discredited. It’s always been intended as a population-level estimate of obesity. There have been a number of studies over the years that have correlated other health outcomes to BMI, but those things are intended to be population-level correlations. For example BMI is correlated with average expected life span, where a BMI in the “healthy” range is correlated with longer average lifespans, and both under or overweight BMIs are correlated with shorter average lifespans. Your specific health situation may vary.
MRI or DXA scans can more accurately determine body fat percentage to determine obesity. Comparing those with BMI has an error rate of around 20% of people being miscategorized as under or overweight.
Bottom line, don’t be sedentary all the time, get physical activity and eat a healthy diet instead of getting too hung up on what metrics are best. Progress over perfection.
I like Harvard’s Nutrition Source for science-based nutrition info that’s easy to read.
For example BMI is correlated with average expected life span, where a BMI in the “healthy” range is correlated with longer average lifespans, and both under or overweight BMIs are correlated with shorter average lifespans.
Actually, there’s a curve where all cause mortality is lowest at BMIs that are slightly overweight, between 25-30 kg/m^2 :
https://pmc.ncbi.nlm.nih.gov/articles/PMC11051237/
So the traditional “overweight” range appears to be slightly healthier overall than the “healthy” range. Perhaps because some healthy people have higher lean tissue mass (muscle, bone density, etc.).
From what I have read, it is body-fat measure that we ought be using, & the plastic-calipers cost something like $5-10, online.
I’d read that in some scientific news thing, a few years ago, sorry don’t remember which one.
_ /\ _
The body fat calliper method is extremely dependent on the person doing the measurement, so it’s more useful for measuring progress. The Navy Method is slightly less variable, and is a pretty good balance between cost, accuracy, and reliability if you’re looking for something. Not as good as DEXA, far better than body impedance, and more accurate than callipers.
Body fat definitely is a better method, up to a point - once someone is definitely into the “obese” or “underweight” on the BMI, there’s a good chance of the person is unhealthy in some way. Bodybuilders achieve worryingly low body fat % with “obese” BMI score, but they can still have plenty of other markers that say they’re unhealthy, and underweight is underweight. But my BMI is ~25 (“overweight”) and ~15% body fat; I’m ok.
A lot of people who are 50% body fat and have a BMI of 35 love to hear that the BMI is flawed.
I just remember as a teen at 16 and my PCP had it in the waiting room. And he swore by it. At 16 I was 6 foot and weighed about 150. And he said I had to much body fat. That I need to go on a diet. My mom the nurse was about to tear him a new asshole before i interrupted and asked Does a fifth of whiskey and a pack of Lucky Strikes a day count? You could hear a pin drop after I said that.
16 years old 6ft tall 150# works out to 183cm 77kg BMI20 (lower mid normal) and I’d put you on a diet and exercise program for sure. To gain weight and muscle. Muscle mass is correlated strongly with quality of life in later years, and you’ve described a string bean. Maybe a skinny fat string bean, but still.
LMAO…so sorry …I am really no sarcasm…but never thought I would ever see in a sentence a skinny fat string bean lol. No my pcp was talking about losing more wieght.
They said you needed to lose weight at 150‽ I’m also 6ft but I have 100lbs on you and I still am dense enough to sink in ocean water. My build would have made your doc have a stroke.
The only people who hate BMI are fat people, and US health agencies who hate the fact that the rate increasing out of control.
Fastest way to decrease your BMI is to lose a leg. The fastest way to increase it is to lose two.
Not all mass is fat, and not all mass is the same.
