The new BMI formula

January 22, 2013, 12:05 pmYahoo!7

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By Alice Treloar

Are you thinner than you thought?


Tall poppy syndrome literally strikes again. A number-crunching academic from Oxford University, Mathematician Professor Nick Trefethen, believes the formula used to calculate body mass index (BMI) – an estimation of how much body fat you’re carrying – is flawed. And it favours the tall.

His theory? The current formulation doesn’t take into account how much natural bulk taller people have, making the Nicole Kidman's of the world too fat and the vertically challenged too thin.

The current BMI calculation is found by dividing weight in kilograms by height in metres squared. If the answer falls:

Under 18 – you’re very underweight and possibly malnourished
Under 20 – you’re underweight and could afford to gain a little weight
20 to 25 - you have a healthy weight range for young and middle-aged adults
26 to 30 – you’re overweight

Over 30 – you’re obese

But Trefethen’s new method suggests multiplying weight in kilograms by 1.3, to allow for more bulk scope. The answer is then divided by a person’s height to the power of 2.5.

Easy, right?

“BMI divides the weight by too large a number for short people and too small a number for tall people. So short people are mislead into thinking that they are thinner than they are, and tall people are mislead into thinking they are fatter,” Professor Trefethen said.

In layman’s terms, this could mean that tall people clear themselves from the overweight or obese category, while vertically challenged individuals could enter the danger zone.

But for the Short Sally’s of the world, don’t fret. Trefethen doesn’t expect his new blueprint to be adopted by health professionals as gospel but does call for health professionals to justify the current calculations.

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9 Comments

  1. Ranjeet11:41am Wednesday 23rd January 2013 ESTReport Abuse

    Nice toes

    Reply
  2. Robert Underwood05:25am Wednesday 23rd January 2013 ESTReport Abuse

    It Is All bunk and poppycock!

    Reply
  3. Quick01:35am Wednesday 23rd January 2013 ESTReport Abuse

    Has anyone actually try the formula? Not much difference

    1 Reply
  4. Chillagoe10:26pm Tuesday 22nd January 2013 ESTReport Abuse

    I know, when I take my glasses off that I am thinner than I think I am.

    Reply
  5. Rt Atk07:29pm Tuesday 22nd January 2013 ESTReport Abuse

    more rubbish, a generalised measure will never work given the variation of peoples shapes and sizes. If you want an estimate on your healthy weight ask your GP.

    Reply
  6. Ghost Hunter05:26pm Tuesday 22nd January 2013 ESTReport Abuse

    This article was written by Alice 'In Wonderland' Treloar.

    Reply
  7. duckman03:27pm Tuesday 22nd January 2013 ESTReport Abuse

    Body-fat scales don't work either. I was assessed ay my gym and the scales said I had 11% fat. Six weeks later, after developing more lean muscle with a reasonably high intensity program, but remaining at exactly the same weight (with a high protein diet with very low levels of fat and sugar) , the same body-fat scales said my body was 22% fat.

    Reply
  8. Samantha02:46pm Tuesday 22nd January 2013 ESTReport Abuse

    I think the BMI has needed to be adjusted for a long time - I don't think that using weight (mass) at all should count for such a huge assessment on whether or not you fall into the "healthy body range". There are so many factors to consider and weight is easily corrupted by different scales of measurement, body shape and muscle mass

    Reply
  9. Glib12:56pm Tuesday 22nd January 2013 ESTReport Abuse

    BMI also does not account for athletic, muscular build. Muscle is very heavy.

    Reply

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