The fallacy of BMI measurements

by Sue Widemark

The newest fad is judging whether a person is 'fat' or 'at risk' (the two are considered the same) using the BMI score.

People questioned how good it was to base medical judgements of risk on the Met-Life weight charts because of the rigidity of the charts. Well, if you thought the charts were rigid, the BMI makes the charts look open minded.
 

BMI or Body Mass Index is based on weight alone.

Just weight. It makes no distinctions for age. It makes no distinctions for muscle mass and it doesn't even distinguish between male and female. This rigid measurement is being aggressively 'sold' to Health Care professionals as 'more convenient' than the weight charts.

It also puts 55 percent of the American people 'at risk' because of 'obesity' since anyone with a BMI over 24 is considered 'at risk', weightwise.

The fallacy of this is, of course, that most of the athletes in the peak of condition are now, according to BMI standards, at risk. This is understandable because athletes are often quite muscular but BMI scoring does not allow for the percentage of muscle mass and muscle weighs 4 times heavier than fat.
 

How to Make BMI Accurate

BMI could be made accurate if the bodyfat percentage were figured in i.e. the amount of weight which is lean muscle mass were counted. But of course, if that were done, there would be no need of BMI at all because a mere measure of bodyfat percentage would tell the story and much more accurately than does BMI.

Perhaps accuracy was not one of the goals of the committee releasing the new standards for obesity including BMI as a suggested measurement of risk, to replace the weight charts for Health Care professionals. These 'standards' advocate dieting for anyone with a BMI over 24.

On the committee, at least THREE of the members had direct links to pharmaceuticals manufacturing diet pills like "Redux". A fourth member, Dr. Pi-Sunyer is the lead scientist for the program advisory committee of Weight Watchers International.

To be fair, these are some of America's brightest scientists in the field of weight management.  However, one might wonder if they wouldn't mind if folks patronized those companies with whom they are affiliated.  This committee, ended up besting the insurance companies who set the "original" "ideal" weights on formula.  They dropped 15-20 lbs off the "ideal weight" rending most Americans (60 percent or more) overweight.  (In defense of Weight Watchers, they don't hold you to your BMI "ideal" weight but rather encourage you and your doctor to find a weight which is comfortable and healthy for you - this is in keeping with the latest research which shows that people tend to be more successful with weight control if they set "reasonable" rather than "fashionable" goals)

BMI is figured on weight alone.  Ideal weights are more to set a ball park range rather than hold to with a religious fervor.  Many doctors use the BMI to signal them that perhaps they should "look for" lifestyle related problems in their patients.

BMI scores render many athletes (with very low bodyfat levels) as "obese".

Best bet - don't get stuck on the numbers.  Use 'weight' as a comparison and accountability to see how well you are doing with weight control rather than using it as a gauge of 'moral superiority' or as something to obscess on.

Healthread!