The BMI measurement is flawed

Interesting piece here on the BMI measurement, I didn't realise the BMI scale was 200 years old!!!!


  • I knew it was complete rubbish when it implies that women should essentially be bulimic in order to get to their "optimum" (wrong word to use) weight which is just skin and bones
  • I was being facetious image
  • It's interesting that it's used for something that its creator said was flawed. As a staistical tool for entire populations, it probably has some uses; when applied to individuals, it (like all other "average based measurments" MHR for example) can't be taken literally.

  • What I find interesting is the importance our health system places on such a fundementally flawed system
  • But as the article says, the more accurate measures are more expensive.

    I also think that there is a lesser amount of the population who is probably over BMI and healthy as opposed to the amount who is over the BMI and really over weight
  • Reading between the lines the article should have been entitled "excuses for Americas obesity".

    Whilst bmi like any average system won't apply to everyone, to most people it does. Even when applied to supposed athletic types, just because a person runs 30 miles (for example) a week, and doesn't eat to excess, it doesn't follow that they are therefore lean and mean. If anything BMI is even more revelent to people who exercise as excercising can lead to self delusion as to how athletic you are.

    The author shows their ignorance in this statement:

    "Because the majority of people today (and in Quetelet's time) lead fairly sedentary lives and are not particularly active"

    So the majority of people, who lived two hundred years ago, and did manual jobs working in the fields all day or mining by hand or working 14 hrs days in a factory etc etc...because nearly every job involved some hard labour not to mention if you wanted to go anywhere most peolpe had to walk there, lead the same sedentry lifestyles as the average four wheel driving, sit in front of the tv, burger eating 21century American?

  • BMI by itself is technicaly bolx. That article is also bolx!

    Sorry but that "article" is written by someone that is just having a rant. The bit about bikes and birthdays? WTF. Insurance industry using it? What else we going to risk fat bastards with? We have a pretty leanent scale. We won't wack you til BMI is over 30, plenty of leaway for the"fit movie star"!

  • I just don't like the idea of catagorising people into 4 boxes, and saying those in 3 of those boxes are unhealthy, things just aren't that cut and dry.
  • I work in GP surgeries and almost every Dr's room I've been in, have a BMI scale on their wall. Didn't realise it was 200 years old!

    The calculations don't seem to take into account frame size. You could have a skinny, unhealthy person eating a v unbalanced diet with a 'healthy' BMI,  then a larger framed, fit and healthy person with an 'obese' BMI - crackers.

    I've always thought everything in moderation is the best approach to being healthy image

  • popsiderpopsider ✭✭✭
    PloddingOn wrote (see)
    I knew it was complete rubbish when it implies that women should essentially be bulimic in order to get to their "optimum" (wrong word to use) weight which is just skin and bones

    I'm not sure about that - 10 stone and 5'6 falls well within the "ideal" weight - unless I'm calculating it wrongly ?  

  • BMI is the guide.

     above 30 the doc should be hinting to loose someweight(I think after a few years of uni they can tell the diffrence between a bit of belly fat and muscled shoulders) If concerned chol and BP checked.

    Bmi above 40........I don't care what you say, your fat and need to loose weight.

  • I like the way my old doctor hinted at me to loose some weight, he asked if I was pregenant!
  • JohnFolJohnFol ✭✭✭
    All I know is I am in the same category as Brad Pitt when he filmed Troy and I know which of the two of us women would prefer.
  • The truth of the matter is that most people that are fat and unfit know this...they don't need BMI or any other method of defining obesity to tell them this...however most choose not to do anything about the problem.

  • the really funny thing is the intro about the study shows the use of BMI for statistical analysis of a population (the intended usage) then the first point rubbishes BMI by saying it's not intended for application to an individual.  Errrrr.........and?  the study wasn't using it on individuals, but on the population. 

    Point 5 about the bad statistics and "average man" is exactly the same point, you can apply an "average man" to a population, but not to an individual, which from the intro, is exactly what the study did........

    Point 6 is just odd, don't understand his point

    Point 7 is also odd, unless of course we're assuming Americans are all utter morons and can't work out for themselves that being 0.1 into "overweight" isn't significantly worse than being 0.1 below overweight.

    BMI is rubbish when used on an individual, but at least it seems the study that the author is using to rubbish, used what appears to be a correct application of BMI. 

  • I think you're spot on with point 7.  Lots of people (not just Americans) are too stupid to work out that there's not a lot of difference between being just within and just outside the "normal" BMI range.  But that's a good reason why it isn't a good measure on an individual level.
  • Bmi isn't precise, obviously, but it works well enough for the vast majority of cases. If your bmi says you're obese, then you almost certainly are.

    Don't blame the possible flaws in the classification system - just lose some fckn weight, fatty. Easy!

  • I honestly don't think a lot of people in western world realise how fat they are. Compare your average Britain, to your average (non starving) Indian.

    All the goal posts have been moved in the devoloped world, what was once considered overweight is now considered normal.

  • Dr.DanDr.Dan ✭✭✭

    image I agree. We have moved the goal posts with respect to our perception of what is "normal".

    BMI is approximate and is only ever going to be a rough guide ... but it gives a huge range for being in the "healthy" region which is supposed to cover "body types" (e.g. 6ft male the range is 10s 3lb to 13s 9lb).

  • I think it is quite weird though as I am still within normal/healthy BMI at 32 weeks pregnant despite having put on a stone but a friend of mine who I have always thought of as v slim is apparently overweight using this calculation,
  • My bmi is just touching the upper limit for my height yet I'm physically pretty fit, have very little fat and I'm not massively muscular either, although I do weight train 2-3 times a week.

    I tend to agree that it's a dumbed down way of showing people which band they fall into, but most people who are aware of their fitness levels and watch what they eat tend to ignore it anyway so it's not massively relevant.

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