I often hear my clients talk about how they are nervous to go to the doctor, because of weigh-ins and BMI conversations. BMI. The most useless “medical” tool that is still being used, in fact relied upon, as a marker for overall wellness. But there are some major flaws in using BMI measurements, as this is not information that actually tells us anything, let alone anything pertinent to health.
So, can we stop using BMI as a measure of overall wellness? The body mass index fails on multiple fronts as an appropriate and accurate tool.
And here's how:
1. The person who dreamed up the BMI said explicitly that it could not and should not be used to indicate the level of fatness in an individual.
2. It is scientifically nonsensical.
There is no physiological reason to square a person's height which is part of the formula used to determine BMI
3. It is physiologically wrong.
It makes no allowance for the relative proportions of bone, muscle and fat in the body. But bone is denser than muscle and twice as dense as fat, so a person with strong bones, good muscle tone and low fat will have a high BMI.
4. It gets the logic wrong.
The CDC says on its Web site that "the BMI is a reliable indicator of body fatness for people." This is a fundamental error of logic. A high BMI does not mean an individual is even overweight, let alone obese. It could mean the person is fit and healthy, with low body fat percentages.
5. It suggests there are distinct categories of underweight, ideal, overweight and obese, with sharp boundaries that hinge on a decimal place.
That's total nonsense.
6. Continued reliance on the BMI means doctors don't feel the need to use one of the more scientifically sound methods that are available to measure obesity levels.
7. It does not take into account fitness level, genetics, ethnicity, socioeconomic factors, age and other important pieces of information about the individual.
So, if you have ever felt defeated by hearing your BMI, know this: it does not define you, nor does it tell you how healthy you are.
