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How do we judge a healthy weight range? BMI is no longer valid?

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  • ForecasterJasonForecasterJason Member Posts: 2,582 Member Member Posts: 2,582 Member
    This just in: people in denial about their size and/or health think the measure telling them they are in denial is inaccurate?

    And people with poor reading comprehension make inaccurate assumptions. Your point would be?

    No.

    Some day you'll figure it out and stop kidding yourself. Or you won't. Either way, no skin off my back.
    The numbers say that if I were under 25 BMI I would also be below average in muscle mass for my weight. The numbers say that if I can achieve 15% body fat at 220 pounds, my muscle mass percentage will be close to the middle of average.
    I don't understand this. Out of curiosity, how large are your wrists? I would say your bone structure must be massive for what you're saying to be true. I don't have access to it right now, but a few weeks ago I found a percentile chart for adults for lean body mass. I highly doubt you would fall in the lower end of the range.

  • MissusMoonMissusMoon Member Posts: 1,911 Member Member Posts: 1,911 Member
    Demaniacle wrote: »
    BMI appears to be a good guideline for most people; however, the issue with BMI is that there are many factors it does not take into account. For example, muscle mass is not well-accounted for, so it's quite possible to have someone who falls in the overweight category prescribed by the BMI scale, but is actually quite fit and lean-looking. Also, frame size is not factored in, either. Someone who is 'smalled-boned' is going to wear the same amount of weight differently than someone who is 'big-boned', assuming all other variables are held constant (height, gender, muscle:fat ratio, etc.).
    There is also a great amount of individual variation that BMI cannot account for. What looks good/is healthy/functional for one person is not going to be the same for another person.

    I know from scans that I am "big boned". The radiologist and my doctor both said that accounts for a very small variance in weight. A couple of pounds, tops.

    You are overstating the differences in people as they relate to BMI. People use extreme and rare outlier examples.
    BMI's that are too low (sub 19) or over 27 are consistently proven to be indicators for serious health consequences.
    edited August 2016
  • MarkusDarwathMarkusDarwath Member Posts: 393 Member Member Posts: 393 Member
    Dove0804 wrote: »

    Had you read and understood everyone else's posts, and had decent reading comprehension skills yourself, you would understand that your personal goals are that of an extreme outlier and will be very hard to achieve and maintain.

    15% body fat is borderline athletic for a male. 40% muscle mass is in the middle of average. Not an extreme outlier on either of these accounts. 6'1" and large frame puts me on the top end of normal, not an extreme outlier. The only way I could possibly be an extreme outlier is if my bone and organ density is off the chart. I suppose this is possible, I don't really know, but I highly doubt it.

  • 3dogsrunning3dogsrunning Member Posts: 27,179 Member Member Posts: 27,179 Member
    I think we should all just throw darts at a board to decide.

    It's not that hard, really. There is no one "ideal" weight for an individual. If you are generally within your BMI normal range or slightly outside the bounds, if your waist is not relatively large, if you like what you see in the mirror, if your health parameters are fine, then you are likely fine.

    BMI is not meant as a diagnostic tool, neither are other things like body fat. Some people may benefit from additional weight like those with bone density issues, other people may benefit from being skinnier than average like those with T2 diabetes. Some people are generally in good health and their "ideal" weight is solely based on aesthetics. For some people being overly muscular is good for their purposes like for body builders, for others being overly muscular is detrimental to their performance like for endurance athletes. It's a sliding scale for individuals, really, people just like to argue the minutia.

    It was a joke.

    I've been saying the same thing you just did the whole time.
  • Dove0804Dove0804 Member Posts: 213 Member Member Posts: 213 Member
    Dove0804 wrote: »

    Had you read and understood everyone else's posts, and had decent reading comprehension skills yourself, you would understand that your personal goals are that of an extreme outlier and will be very hard to achieve and maintain.

    15% body fat is borderline athletic for a male. 40% muscle mass is in the middle of average. Not an extreme outlier on either of these accounts. 6'1" and large frame puts me on the top end of normal, not an extreme outlier. The only way I could possibly be an extreme outlier is if my bone and organ density is off the chart. I suppose this is possible, I don't really know, but I highly doubt it.

    The problem is, you are solely looking at body fat percentage and ignoring total body weight (and every other parameter out there). 15% body fat is not an outlier in and of itself, but the work to achieve and maintain 15% body fat at various weights is definitely not equal. You are talking as if there's a whole slew of people out there who are able to be at a high weight but still maintain a low body fat percentage. This is simply not the case. Those who exist are outliers, and BMI would not apply to them. This is not reasonable to expect of the majority of the population.
    edited August 2016
  • MarkusDarwathMarkusDarwath Member Posts: 393 Member Member Posts: 393 Member
    By the way, this vegan would like a word...

    article_NANBF_6.jpg

    (Sorry, I had to)

    He represents maybe a percent of a percent of vegans?

  • MarkusDarwathMarkusDarwath Member Posts: 393 Member Member Posts: 393 Member
    The numbers say that if I were under 25 BMI I would also be below average in muscle mass for my weight. The numbers say that if I can achieve 15% body fat at 220 pounds, my muscle mass percentage will be close to the middle of average.
    I don't understand this. Out of curiosity, how large are your wrists? I would say your bone structure must be massive for what you're saying to be true. I don't have access to it right now, but a few weeks ago I found a percentile chart for adults for lean body mass. I highly doubt you would fall in the lower end of the range.

    My wrist is just under 8 inches, measured between my hand and the protrusions of the bones on either side of the joint. So 7-7/8".

    I'm basing my calculations on my mass minus fat and muscle percentages as measure by my bio impedance scale. I'll mention again, that at present time, the body fat percentage reported by the scale is within a couple tenths of my BMI number. So I'll concede that the fatter one is, the more accurate BMI seems to be as an estimate of body fat.

    Just for completeness, I'll throw all the math on here. I'm at 262# total. BF% is 34.6 = 90.7# (rounding). Muscle% is 29.5 = 77.3# Remaining lean mass is then 94#. Since I'm an adult and no longer growing, this number should stay the same regardless of what I weigh (barring bone loss in old age). Stated previously, I'm 6'1".

    To achieve a BMI of 24.4, I would have to weigh 185#. If I was at 15% body fat at that weight it would be 27.75# fat + 94# static lean mass = 121.75# non-muscle. Remaining muscle mass of 63.25# = 34% of total mass.
    The first source I was able to find that gave an actual percentage for average muscle mass (link given in a previous post) states that the average for men is between 38 and 54 percent. Thus at a BMI just short of "overweight", and 15% actual body fat, I would be below average for muscle mass.

    On the other hand, if I weighed 220# at 15% body fat, it would leave me with 33# of fat. That plus the 94# of static weight subtracted from 220 leaves 93# of muscle which is 42% of total mass... right in the average range.
    I just now found another site specifying percentages of muscle mass.
    https://quora.com/On-average-what-of-a-persons-lean-body-mass-total-mass-minus-fat-mass-consists-of-muscle
    This one gives average muscle mass for men as being 50% of lean body mass and 40% of total body mass +/- 5%... just what I have calculated.


    I found the link above while looking unsuccessfully for numbers regarding the average non-muscle lean mass. The biggest margin for error in my math would be if my scale were grossly under-reporting my muscle mass or grossly over-reporting my BF% (which would also make the BMI number inaccurate).
    If neither of these is the case, then for me to qualify as an extreme outlier my non-muscle lean mass would have to be significantly above average for my height and gender. I'm big, but I'm not Andre the Giant. Nor am I Gimli, with a bone density comparable to granite (so far as I know).

    So there we have it -MATH-. If someone can site sources showing that my current lean body mass is drastically above the norm for my height and gender, I'm all eyes.
  • MarkusDarwathMarkusDarwath Member Posts: 393 Member Member Posts: 393 Member
    RLester67 wrote: »
    From your link
    BMI, or body mass index, is an estimated measure of the fat composition of the human body, or how proportionate a person's weight is to his height

    That's not the same as estimating actual bodyfat percentage.

    What is composition then, if not percentage? And if you read further on, it does actually state "percentage" down the page a ways.

    Livestrong also states that BMI is supposed to approximate body fat percentage. And they're a site I generally disagree with on a number of topics, as they promote low fat, high carb diets and low mass body compositions.

  • MarkusDarwathMarkusDarwath Member Posts: 393 Member Member Posts: 393 Member
    Dove0804 wrote: »
    The problem is, you are solely looking at body fat percentage and ignoring total body weight (and every other parameter out there). 15% body fat is not an outlier in and of itself, but the work to achieve and maintain 15% body fat at various weights is definitely not equal. You are talking as if there's a whole slew of people out there who are able to be at a high weight but still maintain a low body fat percentage. This is simply not the case. Those who exist are outliers, and BMI would not apply to them. This is not reasonable to expect of the majority of the population.

    I'm also looking at muscle mass percentage. 40% in a male is -normal-, not a high weight.

    I'm also saying that what the "experts" and "authorities" are defining as high weight, is not necessarily high.

    I've put up my math. Let's see some solid numbers and evidence in support of the BMI definitions, because all I've seen so far is blind appeal to authority. The arguments boil down to, "nuh uh. You have to be doing it wrong because you disagree with the experts."
    edited August 2016
  • MarkusDarwathMarkusDarwath Member Posts: 393 Member Member Posts: 393 Member
    Packerjohn wrote: »
    The type of scale you are using is notoriously inaccurate.

    Again, at my present weight, the scale and BMI are actually in agreement. If you are going to assume the scale is wrong, then BMI is also wrong.
    What I see in the mirror also agrees with being around 35% body fat.
  • litsy3litsy3 Member Posts: 783 Member Member Posts: 783 Member
    litsy3 wrote: »


    In any case, using the highly scientific 'looking in the mirror and estimating' technique, I am nowhere near 18.5% fat. I'd say more like 20-21. 18.5 is pretty low for a woman.

    Your profile pic suggests you are a distance runner. Lower than average body fat often goes with the territory.

    I am a distance runner, but I'm nowhere near racing weight just now (and definitely not in that picture!) - that's what I'm doing hanging round on MFP!
    edited August 2016
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