Before I get into the various limitations of BMI, I
must point out that the measure is quite useful
across large populations, as it is well correlated
with the degree of adiposity, and of course it is extremely simple to measure in clinical practice.
ples and pears
For over 60 years, we have known that independent of how heavy a person is, the distribution of
their body weight, or more generally the shape of
their body is a key predictor of health risk. It is now
Nevertheless, here are some of the key issues with well established that individuals who deposit much
BMI, particularly when used on an individual basis. of their body weight around their midsection, the
so called apple-shaped, are at much greater risk of
1. BMI does not differentiate between the
disease and early mortality in contrast to the so calMichelin Man and The Terminator
led pear-shaped, who carry their weight more peOk, we might as well just get this abundantly obvi- ripherally, particularly in the lower body. Thus, two
ous problem out of the way. I have heard countless individuals with a BMI of 32 kg/m2 could have
times how one buff celebrity or another (e.g. Tom drastically different body shapes, and thus varying
Cruise, Arnold Schwarzenegger, The Rock etc.)
risk of disease and early mortality.
would be classified as overweight or obese accorFortunately, a very simple measure allows you or
ding to their BMI due to their excess amount of
your physician to decide whether your elevated
muscle. Yes, this is absolutely true. BMI is a meaBMI is و H\ H܈ X\