8 ms·

The focus on kg/m2 (BMI) I cannot understand. Surely the lowly “body fat percentage” should be a better variable than kg/m2? Bodies are three dimensional you kn

by wjnc 2y ago

The focus on kg/m2 (BMI) I cannot understand. Surely the lowly “body fat percentage” should be a better variable than kg/m2? Bodies are three dimensional you know!

coldpie 2y ago
It is much easier to measure, and is a good enough proxy for the vast majority of people.
- deleted 2y ago
  [deleted]
- bumby 2y ago
  To quantify, I've heard MDs say that the outliers (relatively high BMI but low body fat) constitute less than 1% of high BMI people. They also said that those outliers are still at risk of certain health troubles, like sleep apnea. The suggestion of using BMI + waist circumference is an easier to measure risk factor than bodyfat percentage and helps to better capture those outliers.
mannykannot 2y ago
I imagine the missing spatial dimensions are correlated with weight, for any given height.
swatcoder 2y ago
BMI is trivial to measure conclusively, using tools that are almost universally available and ready. And at population scale, it's proven to be a strong and pretty signal for analyzing in studies like these as the ways in which BMI can fail for individuals is too uncommon for it to matter to population studies. It's a perfect tool to use for studies like these, as it can contribute understanding society-level concerns about the obesity epidemic and what impact we can expect it to have if it continues not to be tackled. But like with almost all medical and nutritional research, drawing conclusions for yourself as an individual based on these population-scale studies is inevitably fraught. In the case of BMI studies, you can often get a fair sense of whether you should be concerned or not, but do need to take into account other things that you know about your lifestyle and health. Your doctor, presumably, does exactly that. Meanwhile, body fat percentage tends to be very hard to measure accurately in the first place and has different techniques that tend to have different error characteristics, making it hard to correlate it between studies done through different clinics, let alone against someone's personal assessment at home or with their personal doctor/trainer/whatever. It probably has high relevance to some medical and nutritional outcomes, but isn't a very useful input variable for research because its inescapably noisy.
- hirvi74 2y ago
  I apologize if this is tangential, but I have noticed BMI research is often heavily criticized, but the same issues that plague BMI can easily be applied to psychometric measurements of intelligence (IQ), but somehow IQ is spared the same beating for some reason I must not understand. Perhaps my low IQ is showing, but why is one metric heavily criticized while the other is not? (Rhetorical)
  - TylerE 2y ago
    Huh? I haven’t seen “IQ” seriously used in decades. Its flaw are well known.
    - hughesjj 2y ago
      Even in popsci/social media I've seen more and more awareness that it's "bunk" science. It's in the same category as all that "alpha male" theory, Meyers Briggs, polygraphs, and "left vs right brained" people. I'm starting to see more awareness around the concerns of "ballistic forensics" too, which is heartening.
      - hirvi74 2y ago
        > Even in popsci/social media I've seen more and more awareness that it's "bunk" science. Devil's Advocate: Then why is it so heavily used still? (Then again, I guess back to my initial point -- the same could be said for BMI.)
        TylerE 2y ago
        Proof that's it's still heavily used in serious scientific literature?
        hirvi74 2y ago
        How do you define 'serious scientific literature?' In other words, what type of evidence would you like me to present? Does any peer reviewed research that uses IQ as a factor count as serious? (Obviously, I won't present research that is about IQ measurement.)
maxglute 2y ago
It's an easier diagnostic metric. Being jacked shit house with high BMI will still suffer from health issues of merely being overweight relative to frame.
- voisin 2y ago
  > Being jacked shit house with high BMI will still suffer from health issues of merely being overweight relative to frame. Do you have evidence for this? (Assuming getting jacked without the use of steroids)
  - fluoridation 2y ago
    Well, for one, it places the same strain on the skeleton, with all the consequences that entails. Mass is mass, no matter if it's muscle or fat.
    - nradov 2y ago
      Well yes and no. Strain on the skeleton from excess muscle isn't particularly a problem unless someone is really huge or does a lot of running. The skeleton adapts to handle the load. Having more strength in the muscles that stabilize joints actually reduces the risk of joint injuries — up to a point. https://peterattiamd.com/belindabeck/ https://peterattiamd.com/belindabeck/ The medical problems with excess muscle mass tend to be more on the cardiovascular system than the skeleton. And the process of gaining a lot of muscle mass can increase the risk of musculoskeletal injuries (especially if using PEDS), which is a key confounding factor when looking at population health statistics.
    - byproxy 2y ago
      Wouldn't some (if not all) of that be mitigated by the increase in bone density that comes with resistance training?
      - fluoridation 2y ago
        The problem is not bone density. Your bones are never going to break under your own weight unless there's something seriously wrong with you. The problem is joint health.
DiskoHexyl 2y ago
Let's put it like this: the probability of an individual to be at a BMI of 30+ AND being very lean, while not using PEDs, is extremely low. So low, in fact, that it doesn't make sense to even look into these outliers from the societal health point of view. Imagine a 180cm 98kg male. That would be a BMI of 30. How often do you see people of that size with visible abs? And of those, how many are the ones who've never touched steroids, sarms, peptides and hgh? If a person's BMI is less than 30, they are going to be okay no matter what their body composition, and with a BMI of 30+ they aren't going to be okay, whether they are fat or jacked. Both obese and insanely built people put massive strain on their knees and back, both typically have high blood pressure. Then the adipose tissue itself has various negative inflammatory effects on health, which sceletal muscle doesn't, and fat people encounter psychological side-effects of being unattractive, which jacked people don't, but PED use has its own list of well-known issues, and being THAT MUCH into bodybuilding is highly correlated with body dysmorphia alongside other physch issues. So both are bad, and when speaking about general population health, we shouldn't really focus on body composition- BMI is good enough marker on its own
- z33k 2y ago
  4 years ago I was 100kg @ 185cm. Never touched PEDs. All it took was being in the gym going all out for around 2 hours, 6 days a week. My body fat was 13% consistently. I tried going below 13% until it started to affect my strength. The rest of my life also revolved around recovery and nutrition because very quickly I realized that I needed to make extraordinary efforts to allow my body to recover from the regimen. I slept 10+ hours and ate around 3300 cals daily (TDEE was massive). Being on antidepressants at the time made eating these amounts much easier, as it seemed to turn off something in my brain responsible for me feeling satiated. I started gym after being diagnosed with the psych issues. I really put 110% effort into it and got… big stretch marks because my muscles grew so fast. I don’t think what I was doing was ”healthy” as much as it was ”I am super depressed and heavy barbell squats is my coping mechanism”. I just wanted to say, you don’t need PEDs to get ”scary” jacked. But you probably need to be crazy like me.
  - DiskoHexyl 2y ago
heraldgeezer 2y ago
If you are not an ELITE athlete or bodybuilder... then BMI is accurate. You are coping.
- blitzar 2y ago
  I'm just big boned.
- Nasrudith 2y ago
  You yourself are coping about the inaccuracy of BMI, what is so hard to accept that BMI is a sucky measurement?
  - heraldgeezer 2y ago
    [flagged] What is so hard to accept that BMI is a good measurement? Imbecile.
hluska 2y ago
Outside of elite athletes, BMI is good at what it’s for. It’s just an easy way to express the relationship between your weight and height. Everything else requires specialized tools and contains a large margin of error.
ropable 2y ago
BMI (as a diagnostic tool for overweight and obesity) has some problems, but it's good enough for most people most of the time. The measurement is FAR less likely to return a false positive (due to someone being "too jacked") than it is to correctly identify some who is carrying too much body fat. In any case, BMI plus a waist circumference measurement is even more accurate, and is still an easy, accessible and useful clinical diagnostic measurement.
NoPicklez 2y ago
Not really, because you can have low body fat and low muscle and be an absolute mess kg/m2 is akin to height and width which is 3 dimensional

by wjnc 2y ago

The focus on kg/m2 (BMI) I cannot understand. Surely the lowly “body fat percentage” should be a better variable than kg/m2? Bodies are three dimensional you know!

coldpie 2y ago

It is much easier to measure, and is a good enough proxy for the vast majority of people.

deleted 2y ago
[deleted]
bumby 2y ago
To quantify, I've heard MDs say that the outliers (relatively high BMI but low body fat) constitute less than 1% of high BMI people. They also said that those outliers are still at risk of certain health troubles, like sleep apnea. The suggestion of using BMI + waist circumference is an easier to measure risk factor than bodyfat percentage and helps to better capture those outliers.

mannykannot 2y ago

I imagine the missing spatial dimensions are correlated with weight, for any given height.

swatcoder 2y ago

BMI is trivial to measure conclusively, using tools that are almost universally available and ready. And at population scale, it's proven to be a strong and pretty signal for analyzing in studies like these as the ways in which BMI can fail for individuals is too uncommon for it to matter to population studies. It's a perfect tool to use for studies like these, as it can contribute understanding society-level concerns about the obesity epidemic and what impact we can expect it to have if it continues not to be tackled. But like with almost all medical and nutritional research, drawing conclusions for yourself as an individual based on these population-scale studies is inevitably fraught. In the case of BMI studies, you can often get a fair sense of whether you should be concerned or not, but do need to take into account other things that you know about your lifestyle and health. Your doctor, presumably, does exactly that. Meanwhile, body fat percentage tends to be very hard to measure accurately in the first place and has different techniques that tend to have different error characteristics, making it hard to correlate it between studies done through different clinics, let alone against someone's personal assessment at home or with their personal doctor/trainer/whatever. It probably has high relevance to some medical and nutritional outcomes, but isn't a very useful input variable for research because its inescapably noisy.

hirvi74 2y ago
I apologize if this is tangential, but I have noticed BMI research is often heavily criticized, but the same issues that plague BMI can easily be applied to psychometric measurements of intelligence (IQ), but somehow IQ is spared the same beating for some reason I must not understand. Perhaps my low IQ is showing, but why is one metric heavily criticized while the other is not? (Rhetorical)
- TylerE 2y ago
  Huh? I haven’t seen “IQ” seriously used in decades. Its flaw are well known.
  - hughesjj 2y ago
    Even in popsci/social media I've seen more and more awareness that it's "bunk" science. It's in the same category as all that "alpha male" theory, Meyers Briggs, polygraphs, and "left vs right brained" people. I'm starting to see more awareness around the concerns of "ballistic forensics" too, which is heartening.
    - hirvi74 2y ago
      > Even in popsci/social media I've seen more and more awareness that it's "bunk" science. Devil's Advocate: Then why is it so heavily used still? (Then again, I guess back to my initial point -- the same could be said for BMI.)
      - TylerE 2y ago
        Proof that's it's still heavily used in serious scientific literature?
        hirvi74 2y ago
        How do you define 'serious scientific literature?' In other words, what type of evidence would you like me to present? Does any peer reviewed research that uses IQ as a factor count as serious? (Obviously, I won't present research that is about IQ measurement.)

maxglute 2y ago

It's an easier diagnostic metric. Being jacked shit house with high BMI will still suffer from health issues of merely being overweight relative to frame.

voisin 2y ago
> Being jacked shit house with high BMI will still suffer from health issues of merely being overweight relative to frame. Do you have evidence for this? (Assuming getting jacked without the use of steroids)
- fluoridation 2y ago
  Well, for one, it places the same strain on the skeleton, with all the consequences that entails. Mass is mass, no matter if it's muscle or fat.
  - nradov 2y ago
    Well yes and no. Strain on the skeleton from excess muscle isn't particularly a problem unless someone is really huge or does a lot of running. The skeleton adapts to handle the load. Having more strength in the muscles that stabilize joints actually reduces the risk of joint injuries — up to a point. https://peterattiamd.com/belindabeck/ https://peterattiamd.com/belindabeck/ The medical problems with excess muscle mass tend to be more on the cardiovascular system than the skeleton. And the process of gaining a lot of muscle mass can increase the risk of musculoskeletal injuries (especially if using PEDS), which is a key confounding factor when looking at population health statistics.
  - byproxy 2y ago
    Wouldn't some (if not all) of that be mitigated by the increase in bone density that comes with resistance training?
    - fluoridation 2y ago
      The problem is not bone density. Your bones are never going to break under your own weight unless there's something seriously wrong with you. The problem is joint health.

DiskoHexyl 2y ago

Let's put it like this: the probability of an individual to be at a BMI of 30+ AND being very lean, while not using PEDs, is extremely low. So low, in fact, that it doesn't make sense to even look into these outliers from the societal health point of view. Imagine a 180cm 98kg male. That would be a BMI of 30. How often do you see people of that size with visible abs? And of those, how many are the ones who've never touched steroids, sarms, peptides and hgh? If a person's BMI is less than 30, they are going to be okay no matter what their body composition, and with a BMI of 30+ they aren't going to be okay, whether they are fat or jacked. Both obese and insanely built people put massive strain on their knees and back, both typically have high blood pressure. Then the adipose tissue itself has various negative inflammatory effects on health, which sceletal muscle doesn't, and fat people encounter psychological side-effects of being unattractive, which jacked people don't, but PED use has its own list of well-known issues, and being THAT MUCH into bodybuilding is highly correlated with body dysmorphia alongside other physch issues. So both are bad, and when speaking about general population health, we shouldn't really focus on body composition- BMI is good enough marker on its own

z33k 2y ago
4 years ago I was 100kg @ 185cm. Never touched PEDs. All it took was being in the gym going all out for around 2 hours, 6 days a week. My body fat was 13% consistently. I tried going below 13% until it started to affect my strength. The rest of my life also revolved around recovery and nutrition because very quickly I realized that I needed to make extraordinary efforts to allow my body to recover from the regimen. I slept 10+ hours and ate around 3300 cals daily (TDEE was massive). Being on antidepressants at the time made eating these amounts much easier, as it seemed to turn off something in my brain responsible for me feeling satiated. I started gym after being diagnosed with the psych issues. I really put 110% effort into it and got… big stretch marks because my muscles grew so fast. I don’t think what I was doing was ”healthy” as much as it was ”I am super depressed and heavy barbell squats is my coping mechanism”. I just wanted to say, you don’t need PEDs to get ”scary” jacked. But you probably need to be crazy like me.
- DiskoHexyl 2y ago

heraldgeezer 2y ago

If you are not an ELITE athlete or bodybuilder... then BMI is accurate. You are coping.

blitzar 2y ago
I'm just big boned.
Nasrudith 2y ago
You yourself are coping about the inaccuracy of BMI, what is so hard to accept that BMI is a sucky measurement?
- heraldgeezer 2y ago
  [flagged] What is so hard to accept that BMI is a good measurement? Imbecile.

hluska 2y ago

Outside of elite athletes, BMI is good at what it’s for. It’s just an easy way to express the relationship between your weight and height. Everything else requires specialized tools and contains a large margin of error.

ropable 2y ago

BMI (as a diagnostic tool for overweight and obesity) has some problems, but it's good enough for most people most of the time. The measurement is FAR less likely to return a false positive (due to someone being "too jacked") than it is to correctly identify some who is carrying too much body fat. In any case, BMI plus a waist circumference measurement is even more accurate, and is still an easy, accessible and useful clinical diagnostic measurement.

NoPicklez 2y ago

Not really, because you can have low body fat and low muscle and be an absolute mess kg/m2 is akin to height and width which is 3 dimensional