[shajznnckfke]

I guess people are downvoting because it’s not super relevant to the discussion, but I have a similar opinion that the BMI normal weight range is unreasonable for me.

I’ve been in these two modes:

1) genuinely overweight with too much fat and not enough muscle

2) nearly overweight according to BMI while very fit, with low fat and high muscle. got here from the other state by exercising a lot, losing fat and gaining muscle.

I think I would have to become totally sedentary again to get rid of my muscle mass and actually reach the lower end of “normal weight” according to BMI, while starving myself and feeling feeble.

[Reelin]

> nearly overweight according to BMI while very fit, with low fat and high muscle

Not knowing you personally, it seems statistically more likely to me that your idea of "fit, low fat, high muscle" is what's at fault here (as opposed to BMI). Sure, you could be an exception. But all things being equal, you probably aren't. (Also maybe I misunderstand - if you mean that BMI was saying you were at the high end of normal then ... isn't that just saying that you're fine?)

(Of course if a medical professional or academic specializing in such matters also thought BMI was inaccurate in your case then I would tend to view things differently.)

[noodlesUK]

(Not OP) I’m not an athlete anymore, but I used to be. It would be physically impossible for me to maintain my muscle mass and have a BMI considered normal, whilst also having a body fat percentage >5%. I know many other (pretty much exclusively taller men) people in the same situation.

[PhantomGremlin]

One classic example of this was Michael Jordan.

In his prime he was considered overweight. BMI is way too simplistic for taller athletes.

https://www.webmd.com/diet/features/how-accurate-body-mass-i...

[Reelin]

I guess it would be interesting to see how those numbers interacted graphically. Are the "bad" areas (ie high muscle mass at reasonable fat percentage) associated with health problems according to experts? Or should people with significantly above average muscle mass be using a different scale instead?

[enemywalker]

I believe a different scale would be helpful for people with above average muscle mass. Check out this research paper: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4890841/

The claim is that BMI does not differentiate between body lean mass and body fat mass. Things like hydrostatic testing are more accurate for determining body fat mass.

[nradov]

DXA scans are about as accurate as hydrostatic testing, and are much more widely available. In most urban areas you can get one for about $50.

[zaroth]

I understand the desire to be contrarian, but BMI is widely regarded as totally obsolete with cheap and accurate ways to actually measure body fat percentages.

It’s well understood that BMI is totally wrong for athletes or anyone remotely muscular.

[Reelin]

> I understand the desire to be contrarian

I assure you that's not my motivation at all. I'm not an expert in that field so I tend to trust the metrics used by the health professionals I encounter.

> BMI is widely regarded as totally obsolete

That is not my impression at all, but again I'm not a subject matter expert here. If you have reliable (ie academic or medical) sources I would be interested in learning more about any current preferred metrics.

[Dylan16807]

> totally obsolete with cheap and accurate ways to actually measure body fat percentages

What do you have in mind? With a bit of searching I haven't found much that's cheap. (Obviously you can take some tape or caliper measurements to improve your numbers but that's neither new nor particularly accurate.)

[altvali]

A digital scale that measures body fat is less than $30.

[Jenda_]

And pretty terrible in my experience (tested two, one noname and one branded, unfortunately forgot the manufacturer/model number).

First, there is a fundamental constrain that it measures impedance only through legs and a little bit of belly, but no upper body (at least here in .cz, no consumer-grade scales have hand electrodes). I do road cycling as the only sport, and therefore get extremely skewed results as I have strong legs, but the rest of the body is much weaker.

Second, the measurements are almost non-repeatable. You get tens of percent difference across measurements, god forbid if you suddenly have moist feet etc. However, both scales used firmware cheating to mask this noise: once you set up a "profile", it will remember the initial value, and then change the following measurements only slightly. However, set up a second profile (preferably with a slightly modified age etc. to prevent advanced firmware cheating) and you get completely different results.

[esyir]

It isn't anywhere near obsolete, not as far as I've seen in both scientific and medical contexts. BMI remains heavily used in many nutritional and disease related studies and remains a common metric in healthcare and public heath.

It's imperfect, but generally correct. More importantly, it's easy to measure. Accurate except for outliers isn't as much of an issue as you think it is, especially as these are generally already accounted for by its users.

[shajznnckfke]

I can believe it. I’m curious what typical body types were like in the hunter/gather societies human evolved in, and whether those are ideal for longevity and quality of life in modern society.

[ridaj]

The kind of hunt that humans are believed to have practiced early on was persistence hunting, which consists of chasing prey over long distances until they are exhausted (the gazelle can outrun any human on a scale of minutes, but not on a scale of hours).

https://en.m.wikipedia.org/wiki/Persistence_hunting

If that is the case then the body type would have been low mass overall, like marathoners.

As for best body type for quality of life today (at least from a health perspective), that seems relatively aligned.

[Reelin]

> and whether those are ideal for longevity and quality of life in modern society

This seems like the real question to me; I assume pre-agrarian humans were biologically optimizing to survive famine. Not being an expert on the subject, I wonder what sort of tradeoffs are associated with intense exercise regimes (and how the balance ultimately comes out with respect to modern society).

[shajznnckfke]

I suppose the low fat / high muscle combination would be unlikely for much of the year in places where it was necessary to store fat for the winter.

[nradov]

Neolithic hunter gatherers were as strong as elite athletes today. Civilization and automation have made us weak and frail.

https://www.popsci.com/prehistoric-women-strong-rower/

[Reelin]

Lacking in raw physical power by comparison, sure. But what health issues do we avoid? Do new health issues arise? Optimality in a complex environment is inevitably a nontrivial trade off; we aren't forced to hunt animals with primitive weapons or contend with widespread famine in the modern world.

[mr_toad]

> But what health issues do we avoid?

Infant and child mortality is much much lower.