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BMI CONTROVERSY‼️🤬

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Replies

  • Cassandraw3
    Cassandraw3 Posts: 1,214 Member
    mph323 wrote: »
    jonewe05 wrote: »
    Well BMI tends to overstate how fat tall and muscular people are, and understates how fat short and non-muscular people are.

    If you're a female, your BMI is almost certainly understating how fat you actually are.

    From Livestrong:

    "This formula states that adult body fat percentage is equal to (1.39 x BMI) + (0.16 x age) - (10.34 x gender) - 9, with gender equal to 1 for men and 0 for women to account for the lower body fat percentage of men."

    The formula itself accounts for the difference in body fat between men and women.

    This formula is incredibly inaccurate. This would imply there is a direct correlation between BMI and body fat percentage, which there is not. Using this formula, I have a body fat percentage of 30.9%. In reality, it is ~26%.

    As others have stated, BMI is a good initial indicator for risk assessment. If you fall within the "healthy" range, you are low risk. If you are outside, it requires more investigation.
  • mph323
    mph323 Posts: 3,565 Member
    mph323 wrote: »
    jonewe05 wrote: »
    Well BMI tends to overstate how fat tall and muscular people are, and understates how fat short and non-muscular people are.

    If you're a female, your BMI is almost certainly understating how fat you actually are.

    From Livestrong:

    "This formula states that adult body fat percentage is equal to (1.39 x BMI) + (0.16 x age) - (10.34 x gender) - 9, with gender equal to 1 for men and 0 for women to account for the lower body fat percentage of men."

    The formula itself accounts for the difference in body fat between men and women.

    This formula is incredibly inaccurate. This would imply there is a direct correlation between BMI and body fat percentage, which there is not. Using this formula, I have a body fat percentage of 30.9%. In reality, it is ~26%.

    As others have stated, BMI is a good initial indicator for risk assessment. If you fall within the "healthy" range, you are low risk. If you are outside, it requires more investigation.

    I didn't comment either way on the accuracy of the BMI calculation. I was disputing the post that stated that because women tend to have a higher body fat percentage it was automatically inaccurate for that reason. My post points out that the difference is accounted for in the calculation.
  • mmapags
    mmapags Posts: 8,934 Member
    jseams1234 wrote: »
    zeejane03 wrote: »
    BMI isn't accurate. Go get a DEXA scan or a BodPod test. Then you can see where you're at.

    BMI is accurate enough for me and it's free. My doctor uses it along with several other markers and all together they create a pretty accurate picture of where I'm at health-wise.

    I'm glad it works for you, however, men and women with a decent amount of muscle on their body could easily find themselves in the "overweight" or "obese" category. Although I do think a lot of people underestimate the amount of body fat they have, the BMI chart isn't always an accurate measure for everyone.

    I have a BMI of 27.7 and I’m relatively lean... however, I certainly wouldn’t call what it took to get here “easy”. I certainly don’t care that I’m “overweight”. Neither does my doctor. I also doubt I’d ever stay lean and cross into “obese” naturally no matter how many years I train towards that goal. We’ve really developed an unrealistic view of what is possible because of popular figures we see in mags and movies who are anything but “natural”.

    I agree, BMI isn’t accurate for everyone - but I think those are a small minority and probably don’t care. Most everyone else just feels insulted by the labels of “overweight” and “obese”, or as you mentioned are hugely oblivious about how much fat they actually carry.

    Agreed. And has been stated multiple times, BMI is a population level measurement of statistical risk not an individual one.
  • zeejane03
    zeejane03 Posts: 993 Member
    zeejane03 wrote: »
    BMI isn't accurate. Go get a DEXA scan or a BodPod test. Then you can see where you're at.

    BMI is accurate enough for me and it's free. My doctor uses it along with several other markers and all together they create a pretty accurate picture of where I'm at health-wise.

    I'm glad it works for you, however, men and women with a decent amount of muscle on their body could easily find themselves in the "overweight" or "obese" category. Although I do think a lot of people underestimate the amount of body fat they have, the BMI chart isn't always an accurate measure for everyone.

    Did you actually read through the thread?
  • mph323
    mph323 Posts: 3,565 Member
    PS regular posters, are you sharing my feeling of deja vu??? - every day or so somebody new chimes in with variation of same objection as somebody else had pages back???? :s:*

    Right? Its like the whole thread starts over every couple of pages.
  • jonewe05
    jonewe05 Posts: 5 Member
    kimny72 wrote: »
    jonewe05 wrote: »
    Well BMI tends to overstate how fat tall and muscular people are, and understates how fat short and non-muscular people are.

    If you're a female, your BMI is almost certainly understating how fat you actually are.

    And what are you basing that on? How is it that you are seeing enough women's BMI, body fat %, and health info in order to make that determination?

    Also @mph323

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2877506/

    "In fact, in men BMI correlated significantly better with lean mass than with body fat. In contrast, in women BMI appears to perform better than men..."

    and

    "Decreasing the BMI cut-off for obesity to ≥ 25 kg/m2 for instance, will still result in misclassifying as obese 38% of men and 16% of women"

    And also

    https://www.ncbi.nlm.nih.gov/pubmed/26669574

    "BMI has a high specificity but a low sensitivity to detect adiposity, and it fails to identify nearly half of women with excess fat mass. We provide evidence that a commonly used BMI cutoff value to diagnose obesity is too high among women."

    There are many other studies like this. Put simply, BMI fails to distinguish between lean mass and fat, and above average levels of lean mass are more common in men than in women.