Why You Should NEVER Use BMI

Options
13

Replies

  • xxcandywrathxx
    xxcandywrathxx Posts: 200 Member
    Options
    Why I dont think the bmi machine counter thingy is correct:

    Im apparently morbidly obese. I am soooo not. I do admit to being overweight but there's no way Im that obese, if you were able to see me you'd know the calculator thing is wrong.
    I blame my legs as I do a lot of running and i think the muscle there is whats making me seem so fat.

    But, I do think the bmi calculator is a good way for beginners to see how much they weigh and get an idea of what they have to lose.
  • cunfewzed1
    cunfewzed1 Posts: 80
    Options

    You made another error by using such a sensational title.

    Why you should NEVER use BMI

    Never?
    Never ever?
    In any circumstance?
    Or just you, and your body in your circumstances?

    Hello pot, you're black.

    This is a SENSATIONAL critique of a title of all things? really?
  • mcarter99
    mcarter99 Posts: 1,666 Member
    Options
    It isn't flawed; you're using it wrong. BMI is meant to track an average over a large population.
    That is exactly the point though. People look at that as a guideline of where they should be, when in actuality it varies WIDELY by individual, and the guidelines it gives would be incredibly unhealthy for some people. Anything that considers the majority of body builders to be obese should probably not be used as a guideline when setting individual fitness goals.
    Saying BMI is flawed is incorrect. It simply isn't meant for your purposes. My vacuum cleaner isn't flawed because it doesn't mop the floors as well, it's just the wrong tool.

    OK, so I made one error in the bottom of my post, stating that it was flawed. the rest of my post is valid. I see a lot of people on here who use it as a guideline on how heavy they should be.


    You will be very suprised how much Lean Muscle you lose when you lose weight. It is very hard to drop 30+ lbs and keep all your lean body mass. I would exspect you to drop about 3-5 lbs from that number meaning you might want to readjust you calculations.

    I agree. You can't just lose 30 lbs. of fat. As you lose significant weight, everything goes down, even your blood volume. Everything that's not fat is considered 'lean mass'. I think it's common to hit a healthy BMI and still be 35% fat.
  • Bakkasan
    Bakkasan Posts: 1,027 Member
    Options
    http://www.leighpeele.com/body-fat-pictures-and-percentages

    Thats a damn good link there.

    Personally any male I know whom is slightly more muscular than a string bean is considered obese by the BMI scale. Hardly "elite athletes" by any standard, just in better shape than said string bean.
  • mcarter99
    mcarter99 Posts: 1,666 Member
    Options
    Lyle McDonald seems mostly respected here (though I can't find his credentials). I recently read something of his and he said BMI was a good tool for all but athletes. I think that was the term he used- "athletes".
  • chivalryder
    chivalryder Posts: 4,391 Member
    Options
    You can't just lose 30 lbs. of fat. As you lose significant weight, everything goes down, even your blood volume. Everything that's not fat is considered 'lean mass'. I think it's common to hit a healthy BMI and still be 35% fat.

    35% BF would be considered obese. I'm 35% irght now, and I'm pretty darn chubby.

    I'm no athlete, and I would BARELY fit into the BMI chart if I were at a healthy BF%.
  • bcattoes
    bcattoes Posts: 17,299 Member
    Options
    You can't just lose 30 lbs. of fat. As you lose significant weight, everything goes down, even your blood volume. Everything that's not fat is considered 'lean mass'. I think it's common to hit a healthy BMI and still be 35% fat.

    35% BF would be considered obese. I'm 35% irght now, and I'm pretty darn chubby.

    I'm no athlete, and I would BARELY fit into the BMI chart if I were at a healthy BF%.

    I woman could maybe be at the high end of a healthy BMI and have BF% of 35. But I doubt a man could. A woman would have to have very little muscle to do it.

    I ride the upper edge of a healthy BMI (without including waist) and I'm about 27% BF (I am female). I'm nowhere near "athlete" stage, but I have decent muscle tone.
  • chivalryder
    chivalryder Posts: 4,391 Member
    Options
    According to the link, 35% BF would still be considered obese, but not by much. 32% is the threshold.
  • Bobby_Clerici
    Bobby_Clerici Posts: 1,828 Member
    Options
    BMI does not take into account any other health variables other than height weight.
    I also track progress with bodyfat. Weight is not the whole picture, and the scale can lie as badly as the man in the mirror.
    You can check here for free: http://www.scientificpsychic.com/fitness/diet.html
    I like this method, because it is easy to take and the results are consistent.
    The bottom line is that we have something definitive to track progress.
    This is it.
    Good Luck!
  • carld256
    carld256 Posts: 855 Member
    Options
    BMI is fine for non-athletes. Most people fit into the range of values, and there's no reason not to use it as a general guideline.
  • taylor5877
    taylor5877 Posts: 1,792 Member
    Options
    At one point in my life I had a BMI of 30 and could see the veins in my obliques and lower abs.

    Basically I would have had to lose 20 lbs of muscle to be "healthy".

    Yet at that weight I'd have to jump thru hoops not to be paying too much for health insurance, life insurance, and to not be harassed by a blanket policy at my job (hypothetical here).

    I'm not 210 now, but I'm also not really overweight at 5'10" 238 now (about 18 % body fat). I've set my "goal" at what I estimate will be my weight when I hit 10% body fat, which is fit by almost anyone's standard.

    Are you sure you're 18%? Because you can take a look at the link below (note the 20% male) and see if you think you're actually near that range. It's hard to tell in your pic, but my guess is that you're underestimating your BF%.
    http://www.leighpeele.com/body-fat-pictures-and-percentages

    I was 250 in that picture...And it's not exactly the best in the world for showing what I look like, but it's the only semi-recent one I have.
  • cheshirequeen
    cheshirequeen Posts: 1,324 Member
    Options
    at 5 ft 5 inches and 150 pounds i am considered overweight. if you look at my pic i am definitely not overweight. i have gained a lot of muscle. even the guy that created it a long time ago said its just a tool of estimation. there are so many factors such as children, athletes, elderly. every person looks different at an exact weight/height. i am happy with my body even though it says im on the cusp of being overweight. also, i wear a size 2/4, so i will never consider myself overweight. i rarely use the scale, i used inches. good luck everybody
  • leia_ophelia
    leia_ophelia Posts: 44 Member
    Options
    BMI is a good guide and in general you can calculate the percentage body fat based on the BMI, but there would be differences for each person. Specifically studies found that Asian population has higher fat % at the same BMI than other populations. For example after losing weight I had a BMI of 22 which is well within the healthy range but stil 30% body fat which is on the slighly higher side of the normal fat percentage range for my age. I got myself a body fat monitor so that I could estimate my body fat percentage without relying on BMI. We can still use BMI as a general guide (which is what it was made for). Just do not an absolute guide, the best way to know if we are healthy is not through numbers but by listening to our body and how it feels.
  • Raducan
    Raducan Posts: 7
    Options
    At one point a few years ago I weighed 147lbs and was 5'4"... making me 'overweight' with a BMI of 25.2. But I was slim enough that the smallest size tops in stores were often baggy on me and had a totally flat stomach. I was also on a novice sports team, exercising several times a week. I guess I'm just naturally heavier or have more muscle mass or something because if that's what I looked like at 25 I think my bones would have been jutting out at 20! My mother had a similar experience; one summer she starved herself until her ribs jutted out and still had a BMI of 27! It's got to be utter crap but unfortunately those who do well on it love to say what a great system it is...
  • myofibril
    myofibril Posts: 4,500 Member
    Options
    BMI is a good guide and in general you can calculate the percentage body fat based on the BMI, but there would be differences for each person.

    Yeah, pretty much.

    Unless you are pretty athletic it is a reasonably valid measure of body fat percentage:

    http://www.ncbi.nlm.nih.gov/pubmed/2043597
  • thelovelyLIZ
    thelovelyLIZ Posts: 1,227 Member
    Options
    I wouldn't say you should NEVER use BMI. For many people, it gives them a good ballpark of where they fall. Is it the end all be all? No. Is it flawed? Yes. But I've consulted it from time to time just as a way of measuring my progress.

    Now if you're trying to put on muscle, obviously it's not real great, but for average sized people, it's okay.
  • insyweensy
    insyweensy Posts: 53 Member
    Options
    bump
  • chivalryder
    chivalryder Posts: 4,391 Member
    Options
    BMI is a good guide and in general you can calculate the percentage body fat based on the BMI, but there would be differences for each person.

    Yeah, pretty much.

    Unless you are pretty athletic it is a reasonably valid measure of body fat percentage:

    http://www.ncbi.nlm.nih.gov/pubmed/2043597

    LOL

    The calculation on there said that I have a BF% of 20%! HAH! That's off by nearly 15%! I have a BF% of 35!
  • mcarter99
    mcarter99 Posts: 1,666 Member
    Options
    You can't just lose 30 lbs. of fat. As you lose significant weight, everything goes down, even your blood volume. Everything that's not fat is considered 'lean mass'. I think it's common to hit a healthy BMI and still be 35% fat.

    35% BF would be considered obese. I'm 35% irght now, and I'm pretty darn chubby.

    I'm no athlete, and I would BARELY fit into the BMI chart if I were at a healthy BF%.

    I woman could maybe be at the high end of a healthy BMI and have BF% of 35. But I doubt a man could. A woman would have to have very little muscle to do it.

    I ride the upper edge of a healthy BMI (without including waist) and I'm about 27% BF (I am female). I'm nowhere near "athlete" stage, but I have decent muscle tone.

    Good to know. I had a personal trainer at a gym test me at multiple sites with calipers, while I was on the top of 'healthy' BMI and she said 35%. I said, "No way." I always wondered if they fudge stuff. I didn't look obese or even overweight. A little squishy but fine. I did a lot of exercise.
  • DonniesGirl69
    DonniesGirl69 Posts: 644 Member
    Options
    "While the formula previously called the Quetelet Index for BMI dates to the 19th century, the new term "body mass index" for the ratio and its popularity date to a paper published in the July edition of 1972 in the Journal of Chronic Diseases by Ancel Keys. BMI was explicitly cited by Keys as being appropriate for population studies, and inappropriate for individual diagnosis. Nevertheless, due to its simplicity, it came to be widely used for individual diagnosis, despite its inappropriateness."

    There you have it.....not appropriate for individual diagnosis.
    That's my story and I'm sticking to it. :wink:

Categories