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To be fair BMI is based on Belgians from the 1850s with all the implications it has. Modern people are much taller (+15 cm for males) and eat a lot more protein

by ywvcbk 2y ago

To be fair BMI is based on Belgians from the 1850s with all the implications it has. Modern people are much taller (+15 cm for males) and eat a lot more protein. So the line between normal and overweight is somewhat blurry. e.g. someone who is 6'3" and weighs 200 pounds is overweight. Which might or might not be the case (but you certainly don’t need to a body builder or invest a lot of time to maintain at least reasonably healthy 18-20% body fat ratio).

gruez 2y ago
>To be fair BMI is based on Belgians from the 1850s with all the implications it has. It's a pretty straightforward formula, and even though the cutoffs might be arbitrary, there's undoubtedly a u shaped mortality curve centered somewhere around 20-25. At a population level I don't think any of that is a relevant factor. No one thinks that your risk of death hinges on crossing an arbitrary line, but being fatter definitely isn't good for your health.
- lolinder 2y ago
  But the question here is whether you can compare the BMI curves of two countries and come to any conclusions, and the answer is pretty solidly "no". Bone density, muscle mass, torso height relative to leg height—none of these things are factored into BMI and all of these vary wildly depending on genes.
  - consteval 2y ago
    > vary wildly depending on genes Being born with worse attributes doesn't mean those attributes are out of the equation. A lot of people die much younger than they should just by poor luck, with little or no control on their end. If you happen to have higher bone density and higher muscle mass just because you have higher testosterone, you're still better off. Sometimes people just get the short end of the stick. That doesn't necessarily mean BMI doesn't work. I've even met smokers, smokers! Who have better cardiovascular health than me and are skinnier. Which really fucking sucks for me.
Retric 2y ago
Veins have a 2D cross section where body’s are 3D. That’s one reason why using height ^2 not height ^3 may better correlate with health. Similarly, cancer risks may scale with the amount of tissue or the surface area for things like skin / colon cancer but it’s hard to see how being taller is beneficial.

by ywvcbk 2y ago

gruez 2y ago

>To be fair BMI is based on Belgians from the 1850s with all the implications it has. It's a pretty straightforward formula, and even though the cutoffs might be arbitrary, there's undoubtedly a u shaped mortality curve centered somewhere around 20-25. At a population level I don't think any of that is a relevant factor. No one thinks that your risk of death hinges on crossing an arbitrary line, but being fatter definitely isn't good for your health.

lolinder 2y ago
But the question here is whether you can compare the BMI curves of two countries and come to any conclusions, and the answer is pretty solidly "no". Bone density, muscle mass, torso height relative to leg height—none of these things are factored into BMI and all of these vary wildly depending on genes.
- consteval 2y ago
  > vary wildly depending on genes Being born with worse attributes doesn't mean those attributes are out of the equation. A lot of people die much younger than they should just by poor luck, with little or no control on their end. If you happen to have higher bone density and higher muscle mass just because you have higher testosterone, you're still better off. Sometimes people just get the short end of the stick. That doesn't necessarily mean BMI doesn't work. I've even met smokers, smokers! Who have better cardiovascular health than me and are skinnier. Which really fucking sucks for me.

Retric 2y ago

Veins have a 2D cross section where body’s are 3D. That’s one reason why using height ^2 not height ^3 may better correlate with health. Similarly, cancer risks may scale with the amount of tissue or the surface area for things like skin / colon cancer but it’s hard to see how being taller is beneficial.