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But also BMI is a crap metric, since it doesn't account for percent fat / muscle.

hn_throwaway_99 4y ago
BMI may be a crap metric for individuals, but not for large population samples. I guarantee you that nearly half of American men aren't at obese-level BMIs because bodybuilders are somehow making a dent in the numbers.
- jdeisenberg 4y ago
  Some interesting information about the BMI in this opinion piece: https://www.npr.org/templates/story/story.php?storyId=106268439 https://www.npr.org/templates/story/story.php?storyId=106268... (Top 10 Reasons Why The BMI Is Bogus)
  - bihla 4y ago
    In case I can save anyone a click, there isn’t a single sentence of that article worth reading. The author simply fails to understand that BMI is a helpful indicator for population metrics, and contorts into crazy positions to fill out a “top 10” list
  - hn_throwaway_99 4y ago
    Sorry, I think pretty much all those reasons are bogus. Yes, 100% agree that, as I said, it isn't a good metric for individuals, and I also agree that the actual calculation is weird - at the end of the day it's still just a ratio of height to weight. But all of this nonsense nitpicking about bone density vs muscle vs fat is irrelevant when using it to look at large population cohorts over time. Looking at weight vs height is a good, easily calculable metric without needing to put everyone in a float tank. The US BMI has skyrocketed over the past 50 years solely because we've gotten a ton fatter. There have also been plenty of corroborating studies that we've also gotten a ton weaker, e.g. studies that look at average grip strength.
    - Ancalagon 4y ago
      Any studies in particular of interest on the strength metrics over time?
      - hn_throwaway_99 4y ago
        https://www.npr.org/sections/health-shots/2016/06/13/481590997/millennials-may-be-losing-their-grip https://www.npr.org/sections/health-shots/2016/06/13/4815909... There are links to the source study in that article.
  - strken 4y ago
    The very first reason is "1. The person who dreamed up the BMI said explicitly that it could not and should not be used to indicate the level of fatness in an individual.", which is the exact point being made: at a population level BMI is useful. Additionally, BMI is imprecise, but imprecise doesn't mean useless. If you took a random sample of people with a BMI of 40+ from across the whole population, almost none of them would be near optimal healthy weight; a random sample of 30+, still relatively few. Those few who are healthy at that BMI know it. BMI's maybe not so useful for someone who's hovering around 19 or 28, but at the extreme edges it's very indicative of body fat.
djtriptych 4y ago
if you're 5'9" / 200lbs you'd better be a powerlifter to be considered fit.
- paulpauper 4y ago
  not necessarily. some people are stocky but not that fat either. Former high school or college football players would fit the bill, or people who do manual labor.
  - User23 4y ago
    Football strength training is basically powerlifting[1]. [1] https://www.goodreads.com/book/show/7116789-the-strongest-shall-survive https://www.goodreads.com/book/show/7116789-the-strongest-sh...
pigsty 4y ago
If you’re the type of person where BMI is irrelevant, you’ll know. But the average American is not doing 300 lb bench presses, and the average person doing 300 lb bench presses is also aware that BMI is meaningless for their case but a somewhat fair reference for others.
JesusLovesEwe 4y ago
You need to go for a walk to do some people-watching if you think there's an epidemic of lean Americans with bulging muscles. Visit a Walmart.
Someone1234 4y ago
CDC's usage of BMI is what it was designed for: To measure populations/as a generalization. Your retort is something people repeat, because they don't seem to grasp that originally the point of the retort was when people are using BMI to discuss individuals (wrong) rather than populations (correct). This is the correct usage. But ultimately there's little data supporting the supposition that Americans have so much muscle they're incorrectly categorized via BMI over population level samples, whereas there is plenty of data suggesting that since the 1970s and the subsidization of corn-created sugar, that Americans have gained body fat.
swatcoder 4y ago
I assure you that that the average American male hasn’t been getting increasingly shredded. BMI may not apply well to you individually, but you can look around and see that there’s a worsening problem that aggregate BMI trends seem to capture.
graeme 4y ago
> But also BMI is a crap metric, since it doesn't account for percent fat / muscle. Sure, but for some reason everyone assumes BMI overstates obesity. The opposite is more likely true. Strength and muscle mass are declining as waist size increases. One study looked at this. BMI found ~30% of the participants were obese. But a body fat analysis showed 60% were obese! Staggering difference, but in wrong direction https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0033308 https://journals.plos.org/plosone/article?id=10.1371/journal...
mensetmanusman 4y ago
It was also a crap metric 50 years ago, and the metric being consistent is what matters.
elromulous 4y ago
Is disagreeing with someone a really a reason to downvote them?
throwaway128128 4y ago
Lol, your average American is 200 pounds of muscle. Right
- thiht 4y ago
  That sounds like a South Park joke, « I ain’t fat, I’m athletic »

BMI may be a crap metric for individuals, but not for large population samples. I guarantee you that nearly half of American men aren't at obese-level BMIs because bodybuilders are somehow making a dent in the numbers.

jdeisenberg 4y ago
Some interesting information about the BMI in this opinion piece: https://www.npr.org/templates/story/story.php?storyId=106268439 https://www.npr.org/templates/story/story.php?storyId=106268... (Top 10 Reasons Why The BMI Is Bogus)
- bihla 4y ago
  In case I can save anyone a click, there isn’t a single sentence of that article worth reading. The author simply fails to understand that BMI is a helpful indicator for population metrics, and contorts into crazy positions to fill out a “top 10” list
- hn_throwaway_99 4y ago
  Sorry, I think pretty much all those reasons are bogus. Yes, 100% agree that, as I said, it isn't a good metric for individuals, and I also agree that the actual calculation is weird - at the end of the day it's still just a ratio of height to weight. But all of this nonsense nitpicking about bone density vs muscle vs fat is irrelevant when using it to look at large population cohorts over time. Looking at weight vs height is a good, easily calculable metric without needing to put everyone in a float tank. The US BMI has skyrocketed over the past 50 years solely because we've gotten a ton fatter. There have also been plenty of corroborating studies that we've also gotten a ton weaker, e.g. studies that look at average grip strength.
  - Ancalagon 4y ago
    Any studies in particular of interest on the strength metrics over time?
    - hn_throwaway_99 4y ago
      https://www.npr.org/sections/health-shots/2016/06/13/481590997/millennials-may-be-losing-their-grip https://www.npr.org/sections/health-shots/2016/06/13/4815909... There are links to the source study in that article.
- strken 4y ago
  The very first reason is "1. The person who dreamed up the BMI said explicitly that it could not and should not be used to indicate the level of fatness in an individual.", which is the exact point being made: at a population level BMI is useful. Additionally, BMI is imprecise, but imprecise doesn't mean useless. If you took a random sample of people with a BMI of 40+ from across the whole population, almost none of them would be near optimal healthy weight; a random sample of 30+, still relatively few. Those few who are healthy at that BMI know it. BMI's maybe not so useful for someone who's hovering around 19 or 28, but at the extreme edges it's very indicative of body fat.

djtriptych 4y ago

if you're 5'9" / 200lbs you'd better be a powerlifter to be considered fit.

paulpauper 4y ago
not necessarily. some people are stocky but not that fat either. Former high school or college football players would fit the bill, or people who do manual labor.
- User23 4y ago
  Football strength training is basically powerlifting[1]. [1] https://www.goodreads.com/book/show/7116789-the-strongest-shall-survive https://www.goodreads.com/book/show/7116789-the-strongest-sh...

pigsty 4y ago

If you’re the type of person where BMI is irrelevant, you’ll know. But the average American is not doing 300 lb bench presses, and the average person doing 300 lb bench presses is also aware that BMI is meaningless for their case but a somewhat fair reference for others.

JesusLovesEwe 4y ago

You need to go for a walk to do some people-watching if you think there's an epidemic of lean Americans with bulging muscles. Visit a Walmart.

Someone1234 4y ago

CDC's usage of BMI is what it was designed for: To measure populations/as a generalization. Your retort is something people repeat, because they don't seem to grasp that originally the point of the retort was when people are using BMI to discuss individuals (wrong) rather than populations (correct). This is the correct usage. But ultimately there's little data supporting the supposition that Americans have so much muscle they're incorrectly categorized via BMI over population level samples, whereas there is plenty of data suggesting that since the 1970s and the subsidization of corn-created sugar, that Americans have gained body fat.

swatcoder 4y ago

I assure you that that the average American male hasn’t been getting increasingly shredded. BMI may not apply well to you individually, but you can look around and see that there’s a worsening problem that aggregate BMI trends seem to capture.

graeme 4y ago

> But also BMI is a crap metric, since it doesn't account for percent fat / muscle. Sure, but for some reason everyone assumes BMI overstates obesity. The opposite is more likely true. Strength and muscle mass are declining as waist size increases. One study looked at this. BMI found ~30% of the participants were obese. But a body fat analysis showed 60% were obese! Staggering difference, but in wrong direction https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0033308 https://journals.plos.org/plosone/article?id=10.1371/journal...

mensetmanusman 4y ago

It was also a crap metric 50 years ago, and the metric being consistent is what matters.

elromulous 4y ago

Is disagreeing with someone a really a reason to downvote them?

throwaway128128 4y ago

Lol, your average American is 200 pounds of muscle. Right

thiht 4y ago
That sounds like a South Park joke, « I ain’t fat, I’m athletic »