> there are plenty of people who have "healthy obesity", on account of muscle mass.

There are _very few_ people who have a BMI over 30 purely by having an extreme amount of muscle mass and most of them are on steroids. Also, there are weight related issues for which it is irrelevant whether the extra weight is fat or muscle mass.

BMI has a problem with tall people.

Yes, BMI has problems, but "there are so many hypermuscular people that it makes BMI obsolete" is certainly not one. Ironically, people with normal weight but high body fat percentage ("skinny fat") are one of the problems of BMI, which is almost never brought up by BMI critics.

Actually according to studies BMI underestimates body fat. And by a substantial margin too. About 40% of people classes as not obese by BMI are actually obese.

Very few in the other direction; this study doesn't mention them

>Mean BMI was 27.3 (SD = 5.9) and mean percent body fat was 31.3% (SD = 9.3). BMI characterized 26% of the subjects as obese, while DXA indicated that 64% of them were obese. 39% of the subjects were classified as non-obese by BMI, but were found to be obese by DXA. BMI misclassified 25% men and 48% women. Meanwhile, a strong relationship was demonstrated between increased leptin and increased body fat.

https://journals.plos.org/plosone/article?id=10.1371/journal...

> most men who go to the gym frequently are in the category of "healthy obese"

Healthy obese because of muscle mass is the size of an NFL linebacker, not “most men who go to the gym”

ETA: yea, just checked. TJ Watt has a BMI of 30.7 (barely obese BMI). BMI only matters here if you’re TJ Watt lmao

Overweight BMI is 25 and above, and you can reach that pretty easily if you're a man and you weight lift consistently for a couple of months.

> you can reach that pretty easily if you're a man and you weight lift consistently for a couple of months

and also have significant body fat. Having a BMI over 25 and being lean is not something you can achieve by just going to the gym a few months. It takes time to build muscle.

> I would say that most men who go to the gym frequently are in the category of "healthy obese", or overweight, if you just take into account their BMI.

Maybe it’s regional, but that’s not what I see in the places I’ve lived.

Almost all except some of the young just-post-college athletes are clearly bulked out with fairly high body fat and plainly inverted waist to hip ratios. They can perform a handful of lifts at high weight, but have negligible cardio conditioning, poor engagement of support muscles and stabilizers, and many are sporting progressively worsening back issues.

The trend in gym practice for men, around me, seems to be really poorly matched to healthfulness in general and shows very little evidence of producing lean high-BMI results. But again, maybe its regional.

I believe nobody is confusing Arnold or Hulk Hogan as obese.

In the case of Hogan, I think you can find photos of him in the 1980s where he looks overweight. He was muscular enough that it didn't matter much, but he was far from being "ripped". He downsized in the 1990s and I think he looked better for it.

It’s a different context to the article, but I think you make a reasonable point in that BMI is often used in stupid ways.

For example, when I went to get life insurance, the rate was affected by BMI, regardless of body composition.

"there are plenty of people who have "healthy obesity", on account of muscle mass."

The sheer amount of muscle you would need to exceed BMI 30 (obesity threshold) is pretty rare to see "in the wild" and you have to ask how many such people abused steroids etc. to grow so muscular. Natural Homo sapiens build is fairly lean, we are no Neanderthals.

A very fit guy from a normal city gym may have BMI in the overweight territory (so, say, 26-27), but > 30 is too much.

Yeah I think a lot of people confuse the overweight category with the obese category in these discussions.

I think you're imagining that they have an insane amount of muscle with low body fat, but I'm saying somebody who could be at the higher end of healthy body fat but with plenty of muscle might actually be overweight or even obese by BMI, even if they are perfectly healthy.

Nobody who is jacked has ever been considered obese. This weird "gotcha" about bodybuilders and alike having the BMI of an obese person and being healthy is a meaningless edge cases that tries to stray away discussions.

The vast majority of people are not gym rats, thus their BMI roughly corresponds to their fat levels, correctly approximating overweightness and obesity.

Are bodybuilders really healthy though? I'm sure it's healthier than being obese but the kind of pressure they put on their body, I wonder if that doesn't cause problems. Like with most things done in extreme amounts of course. Many top athletes also have major issues later in life.

And that's not even mentioning the hormones..

You've missed the point of BMI. It's a population metric. The application of it to the individual really only works in the edges (too skinny, too fat) where it becomes obvious. I've never seen a BMI confidence interval (doctors are bad at statistics) but I would imagine the 95% CI would reveal the exact thing you stated. I am an example of this as well. By DEXA I measure at ~19% bodyfat yet my BMI is 27.6. However, it has never been a problem of misdiagnosis and a doctor has never been compelled to bring up my weight.

This argument you're presenting is used by the "fat positivity" movement to discourage the use of population measures that ARE effective in creating useful statistical analysis of health risks. Like all animals humans are subject to the laws of physics. When you have more mass per unit height your body has to work harder. If you then go on and continue to add or maintain this mass you develop health problems. You don't need an MD to see the intention of the metric nor the absurdity of promoting fatness as a "positive" trait. The only thing this reveals is that the progressives have gaslighted society into believing a lie by using "science" as a kudgel to beat you into compliance with.