OT: BRI is the new BMI...

[vav]

I have seen / read a few threads around BMI here on the forum and this NYT got my eye...it's gifted so hopefully those interested can access it.

https://www.nytimes.com/2024/09/06/h...smid=url-share

[XXtwindad]

Yeah, I read that. And commented on it. No, no, and no again. A very poorly researched article.

My comments:

“Even adiposity misses the mark. Someone with a bit of a belly who exercises frequently is going to be in better shape than someone who chain smokes and is “thinner.”

We need a completely new paradigm that utilizes actual fitness and health metrics rather than mere numbers. Can you walk up a hill? Can you lift yourself off the ground? Are you flexible? Do you have good balance? How is your social circle?”

[prototoast]

Without doing any research beyond the article, a few thoughts that come to mind:

-I suspect that BMI and BRI are highly correlated.
-I suspect that there are examples where BRI scores do not accurately reflect health metrics similar to what has been found for BMI.
-It's not clear from the article whether BRI is actually a better predictor of mortality or other health risks than BMI.

[dmitrik4]

The author of the article isn't qualified to draw that final conclusion, and properly doesn’t attempt to.

Originally Posted by XXtwindad

Yeah, I read that. And commented on it. No, no, and no again. A very poorly researched article.

My comments:

“Even adiposity misses the mark. Someone with a bit of a belly who exercises frequently is going to be in better shape than someone who chain smokes and is “thinner.”

We need a completely new paradigm that utilizes actual fitness and health metrics rather than mere numbers. Can you walk up a hill? Can you lift yourself off the ground? Are you flexible? Do you have good balance? How is your social circle?”

Is it a poorly researched news article about this new metric, or are your criticisms aimed at the validity of the metric itself? It seems like the latter. The article is simply reporting on the thing and isn’t supposed to validate or rebut its scientific merit; it’s a newspaper, not a scientific journal.

FWIW, I agree with you—body shape is a terrible proxy for fitness, which the article does note.

[fourflys]

the Coast Guard changed from a max weight to BMI a few years after I joined, so I dealt with BMI for the majority of my 30 yrs.. at least they did account for age at certain points (40+ and then 50+) regarding your max BMI.. I always made it, but some years were just barely.

but to some of the points made, I knew many folks pushing the max BMI (and obese by the normal BMI standards) that could pick someone out of the water and up onto a boat.. I knew one rescue swimmer (the folks who jump out the helos into the Gulf of Alaska, etc) that would probably have been in the upper numbers by the looks of him..

so I'll be interested to see how this new metric shakes out.. But, IMHO, if you want to have a true measure of health, use some type of physical test.. Coast Guard uses a combo of sit ups, push ups, and cardio (either run or swim) as an option to BMI..

[XXtwindad]

Originally Posted by dmitrik4

The author of the article isn't qualified to draw that final conclusion, and properly doesn’t attempt to.



Is it a poorly researched news article about this new metric, or are your criticisms aimed at the validity of the metric itself? It seems like the latter. The article is simply reporting on the thing and isn’t supposed to validate or rebut its scientific merit; it’s a newspaper, not a scientific journal.

FWIW, I agree with you—body shape is a terrible proxy for fitness, which the article does note.

The author doesn’t delve into the history of the BMI at any great length. I understand that wasn’t imperative for the narrative. But it was faulty science to begin with. It was actually designed by a Belgian astronomer in the 1830s with no background in health.

As both a personal trainer and journalist, I was doubly irked by the article. The BMI has long been one of my pet peeves.

[XXtwindad]

Fun fact: when the U.S. brought their BMI standards in line with the WHO’s measurements in the late 90’s, “overweight” went from a 27.8 BMI to 25 BMI cut-off. So, in essence, millions of people went to bed a normal weight and woke up overweight.

I had a potential client approach me a few months ago desperate to lose five pounds. When I asked him why, he pointed to the BMI. This individual had assiduously avoided exercise his entire life. I tried to convince him that, in order to be healthy, he needed to have functional strength and work on cardiovascular endurance. But he was adamant he wanted to lose five pounds before anything else.

[JMT3]

BMI is designed for the average person. Many athlete’s are not the average person. Even my daughter who is a doctor tells me that mine is way off. How? While at the upper end of the acceptable range, I hit the gym and weight train so muscle is heavy and while another couple of points would have me too heavy per BMI I’m less than 8 percent body fat.

I refuse to get on the scale whenever in a medical facility. They so far have honored my request to not weigh.

[nmrt]

Exactly. BMI works at the population level. Just because one individual is classified "normal" by the BMI index does not necessarily mean that the individual is healthy.

It is simply one part of the metric to evaluate health. It works for the vast majority of the population. And when in doubt of what it is predicting, other tests can be performed to evaluate health.

I would not rule what BMI suggests just because it dose not work for a few people.

Originally Posted by JMT3

BMI is designed for the average person. Many athlete’s are not the average person. Even my daughter who is a doctor tells me that mine is way off. How? While at the upper end of the acceptable range, I hit the gym and weight train so muscle is heavy and while another couple of points would have me too heavy per BMI I’m less than 8 percent body fat.

I refuse to get on the scale whenever in a medical facility. They so far have honored my request to not weigh.

[benb]

Originally Posted by nmrt

Exactly. BMI works at the population level. Just because one individual is classified "normal" by the BMI index does not necessarily mean that the individual is healthy.

It is simply one part of the metric to evaluate health. It works for the vast majority of the population. And when in doubt of what it is predicting, other tests can be performed to evaluate health.

I would not rule what BMI suggests just because it dose not work for a few people.

This is the key, people who complain about these measures are complaining because they don't like the way a population level metric classifies them as an individual.

That's not the point. BMI or BRI can screw up on you but still be useful and predictive for a population and correlate well to health risks.

It's a straw man.. if your doctor is not telling you something is wrong stop worrying about it. If you don't go for physicals, then start.

[fourflys]

Originally Posted by benb

This is the key, people who complain about these measures are complaining because they don't like the way a population level metric classifies them as an individual.

That's not the point. BMI or BRI can screw up on you but still be useful and predictive for a population and correlate well to health risks.

It's a straw man.. if your doctor is not telling you something is wrong stop worrying about it. If you don't go for physicals, then start.

one thing that hasn't been discussed so far is how BMI was used, I think back in the 60s, to create insurance actuary tables.. so basically, BMI was "weaponized" by the health insurance industry to determine rates based on this standard.. and I don't have any citations on this currently and, to be honest, I don't feel like looking them up.. so take it with a grain of salt I guess..

some of the military (at least Coast Guard and Air Force) have started using abdominal measurement for semi-annual weigh-ins.. (you can still meet max weight or BMI or fitness test as well for Coast Guard) the idea is if your gut is 39" or less, you are at an acceptable level.. they aren't saying you're healthy, but healthy enough I guess.. I can see some good data behind that if you looked at the health of most people that had a 40" or above waist.. heck, just look at the size charts for any cycling bibs.. the waist measurements would have you thinking any cyclist with a 38-40" waist will be over 6' tall.. not really realistic..

[Andy340]

The examples are interesting “ Dr. Thomas’s paper included a graphic illustration worth the proverbial 1,000 words. It depicted three figures: a lean man who is 5-foot-8 and has a 27-inch waist; a muscular man who is 5-foot-6 with a 29-inch waist; and one with more fat than the others who is 5-foot-6 with a 36.6-inch waist. Each had a B.M.I. of 27.”

The ‘lean’ man at 5 ft 8” would need a weight approx. 178lbs to get a BMI of 27; a 27” waist is very low (<5% adult males) consistent with being lean so that individual would require a lot of muscle to make that weight and likely similar if not more muscular than the ‘muscular’ man with waist of 29” who would need a weight of 168lbs to get a BMI of 27 at 5 ft 6”

These are population outliers so would expect them to differ in body composition from someone closer to average.


‘Roundness’ will also have outliers e.g. very healthy athletes that require adiposity like Atlantic swimmers who will have large waist measurements vs ‘ideal’ but likely subcutaneous fat and not visceral.

[pdonk]

As someone who is mathematically challenged, I had chat gpt run my number for BRI. Unless something went really wrong, I am nearly 2x the max "roundness" as someone my height should be. If you ask most people to look at me, they would say I look relatively fit and not over weight. I know I carry a bit of flab around my middle, but almost everyone in their 50's could use to change their body composition to be leaner or lose a pound or 2.

After an 18 month slog through my mystery illness with Drs, some of who put me on drugs to gain weight and being told by others I need to lose weight, I am skeptical of any value that is based on a mean body shape.

[bigbill]

Back in the day, while I was still in the Navy, twice a year you had to "rope and choke" to determine your body fat. A waist/neck ratio used but at the time, height was not considered. Then height was added. Before that, a friend of mine was tagged as obese because he had a 38" waist and a 14" neck. He was 6'6" and 180 pounds. The width of his hips gave the 38 waist. You could see his ribs. He got a waiver but others did not. Then they created a height/weight chart. If I was under 206 pounds, I did not need to be measured.

I still hear, I may be fat, but I'm in good shape. I was the same way but a cardiologist told me to lose weight or be miserable for the remainder of my shortened life. I lost 60 pounds and I felt better.

[jimcav]

As others have pointed out, it is a population screening metric.
In the Navy, we had so many trigger on BMI, and then they'd go get various skin fold caliper measurements at the medical clinic. I'd bet 98% passed, because we never had too many in the remedial fitness program to get within standards.

Once upon a time the navy kicked out those who failed BMI/calipers, but after we started getting into the sandbox, folks deliberately gained wait to get separated, so they changed the automatic discharges for weight.

BMI is a really simple metric. Federal Fire Fighter candidates get screened for metabolic syndrome--that requires blood pressure, waist circumference, fasting blood sugar and cholesterol. That isn't simple. How both are (should be) used is to screen for who needs to get more medical evaluation etc.

A bit of a drift but somewhat related in terms of screening for fitness, when I was stationed with a SEAL group there were many who seemed "fit" who had trouble with functional movement screening we implemented as we transitioned to the 'tactical athlete' program. The military made big efforts to restructure fitness to both prevent injury and better achieve missions.

Here is a published article on USMC Combat Fitness Test that is somewhat relevant to this conversation:
https://journals.lww.com/nsca-jscr/f...ass_is.17.aspx