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NakoL1 t1_iueh5uq wrote

Yes, but—such skeletal differences only amount to 2-3 BMI units or so

There are genetic differences in muscle mass as well. For instance men tend to have much more upper body (shoulders/arms) muscle mass than women, but there are similar differences between individuals too. Again this can amount to 2-3 BMI units

That's why some people have a baseline BMI of 18, whereas others will have a baseline BMI of 25. That's quite exceptional though, for most people 20-23 will be normal

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chazwomaq t1_iueqhsg wrote

>Yes, but—such skeletal differences only amount to 2-3 BMI units or so
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>...
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>That's why some people have a baseline BMI of 18, whereas others will have a baseline BMI of 25. That's quite exceptional though, for most people 20-23 will be normal

This is really interesting. Do you have sources for this you can share?

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fliguana t1_iufbqvg wrote

Yes, BMI is grossly inaccurate for fitness estimates.

Bodybuilders in show condition have 2-3% body fat, and a BMI of 35+. They are not fat, but have big dense muscles.

BMI may be generally ok to use for young people who do not exercise and don't have physically demanding work or hobbies.

For male members or the high school chess club, high BMI is likely to select overweight kids, but you can also just look, ffs

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barefeet69 t1_iugvoy4 wrote

BMI is perfectly fine to use for most individuals who aren't athletes. Because the only instance it isn't a good estimate for obesity, is with high muscle mass. The vast majority of overweight people are not athletes and it's extremely unlikely that they have high muscle mass.

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34Ohm t1_iugywpf wrote

Ya just like most things, it’s in a normal distribution with outliers. At both ends of the distribution the BMI measurement falls apart and doesn’t apply well (extremely skinny, extremely obese/extremely muscular). But for >95% of the population it’s a good estimate.

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