So two examples of individuals that are using huge amounts of anabolic steroids is "illustrative of the weakness of bmi?" Give me a break. All measures are going to have edge cases. And by the way, those two guys actually are pretty unhealthy -- your body is not made to carry around that much weight.

Ok, what about me?

I’m a 50-something desk jockey, and I’ve never used steroids or any sort of PED. I just eat well, make an effort to exercise, and my genetics steer me towards muscle building. I was also an athlete when I was younger (not sure if this matters).

I mentioned the rock and Arnold were extreme examples, but they were there to make a point… bmi is not meant to be used to measure individuals.

Your body doesn’t really carry the weight though, when it’s muscles.

Your skeleton is there to give the muscles something to form around. Your muscles are supporting the body, not the other way around.

It’s not like your body has to drag around muscles like it’s a burden…

I’ll criticize the crudeness of BMI as a yardstick for fitness as much as the next guy, but absolutely no one is looking at Arnold’s BMI and thinking “huh, BMI says the terminator is obese therefore it’s okay for me to be obese”. They’re getting this idea from somewhere else, and that somewhere else is a nexus of social media and bizarre fat positivity propaganda that’s leaked out from obscure corners of society and into the mainstream.

Ok, what about my bmi?

The point in using extremes and then a more modest (and probably realistic) example of myself was that BMI is a potential trap for anyone who has muscle (even if they are, in fact, very fat). They will most likely be rated a category or two above where they should be, and a weight loss regimen for someone who is “extremely obese” versus someone who is merely “overweight” will probably look very different. Specially, one will probably be a major intervention or lifestyle change, while the other is most likely a small/medium lifestyle change.

My point is this somewhat pedantic argument about BMI does not matter. The phenomenon of "healthy at any weight" is not hinging on cases where BMI does not capture athletic fitness, or does so poorly. "This guy has a BMI of 28.6 and does power lifting! Checkmate bodyshamers!" is not the logic being used in attempting to coerce people into thinking that obesity is healthy.

1. The original commenter asked “how could someone come to believe otherwise?” My “pedantic argument” answered his question.

2. Note the article is about how BMI is a bad measure for many weight types and frequently miscategorizes risk (e.g., by underweighting risk to “normal” bmi folks with a high body fat %).

The argument that I’m trying to make is not to “checkmate bodyshamers”, it’s to show that bmi is overall a pretty bad measure to use to evaluate weight and health in individuals that include a variety of body types.

Fwiw, I’m not a fan of the “healthy at any weight” stance (that’s clearly BS), but I am definitely trying to show that commonly held beliefs about things like BMI even and especially in the medical community can be dangerous and irresponsible (just like the article explains).

Weight being mostly of muscle is different than mostly of fat. When we say obese, it's the later one.

> When we say obese, it's the later one.

Really?

Would you mind telling that to my former doctor who wrote down in my chart that I was “obese” just based on my height, weight, and a quick visual scan? She was starting into “substantial lifestyle change” talks before I showed her my data.

She didn’t reverse course until I showed her my dexa scan and told her my diet and exercise regimen.

My point is that there are plenty of people who are labeled a category or two worse than they actually are. Yes, many people are actually obese — I get that — but people who are naturally muscular quickly grow tired of (and sometimes numb to) being categorized as worse than they actually are.

Folks who talk about obesity, especially medical folks and media folks, would do well to be more nuanced in their analysis and discussion of the data.

The opposite is often the case too though. There are plenty of fat, beer-bellied dudes who think they aren't obese because they have some muscle.

Socially you're right, we wouldn't call someone obese for being incredibly ripped. But in other areas, we classify people as obese or overweight based on BMI, where a ripped person is probably overweight or obese.

What about something like ABSI? https://www.omnicalculator.com/health/a-body-shape-index

There are multiple such measures. Ones I could think of right off the bat is hip/waist ratio, BAI, or simply waist circumference.

Those all fail to reliably predict body fatness in all populations.

All of those measurements should be taken in context with other health signs, like blood pressure, fasting glucose and maybe eating/exercise habits as well.