Is BMI BS?

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  • jjs22
    jjs22 Posts: 156
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    I would say that BMI is *NOT* BS. It just isn't the best tool out there, by a long shot.

    The advantage of BMI, which I'm sure is the only reason for anyone every suggesting it, is that the data is a) extremely simple to collect, and b) has already been collected for huge populations. Suppose you wanted to look at the relation of "overweightness" to heart disease for a population of 100,000 subjects, some in modern western cities, some in traditional societies. Are you going to do full immersion body fat measurements in the Kalahari ? Suppose you want to compare a current-day population to populations from 1950, 1900, 1850. Are you going to travel back in time ?

    So for researchers who want to ask these kinds of questions, there are clear advantages to having a simple number that can be calculated from data that is universally available. Then, the problem is, any conclusions of such a study can only make claims about health that are expressed in terms of BMI. There's no way to "translate" the results into a different, better indicator. That's why your doctor has no real choice but to use BMI, even though he/she probably realizes how primitive it is. Their job is to stay current with recommendations made by public health "experts" and pass them on to their patients. And BMI is the coin of the realm among the "experts".

    For an individual who wants to be fit and healthy, BMI is pretty silly. Do you plan to change your height ? Probably not. Since any changes in BMI are going to be due to weight alone, just ditch BMI and use weight.

    And, as we all know, there's good weight (muscle) and bad weight (excess fat). So what do you do ? Measure the fat ! But some people store more fat on the surface, some store more on the inside, around their organs. So if you take one more simple measurement (skin pinch, say), what do you do with it ? Well, you can compare it to a statistical distribution of a whole lot of other people and see where you fall. (That is, you can use a formula and "convert" it into percent body fat.) That can be useful for getting a general idea, but again it still doesn't say anything precise about you.

    So what to do ? Go ahead and make the measurements. Weight for sure, and maybe waistline, skin pinch, whatever else you want. Watch the trend as your diet and exercise progress. Pick a goal if you want. But unless you have to "make weight" like a wrestler or boxer, or unless you *have* to meet a certain BMI due to someone else's braindead policy, just think of them as numbers.
  • yanicka
    yanicka Posts: 1,004 Member
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    Yanicka... your hot...

    thanks everyone, I will get as close as I can but I will not lose sleep over it.

    Blush!!!! Well thank you ;)

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