Why BMI does not tell the full story...
Body Mass Index' biggest flaw is that it does not take into account the person's body fat versus muscle (lean tissue) content.
Muscle weighs more than fat (it is denser, a cubic inch of muscle weighs more than a cubic inch of fat). Therefore, BMI will inevitably class muscly, athletic people as fatter than they really are.
A 6ft-tall Olympic 100 meter sprinter weighing 90kg (200lbs) may have the same BMI (26) as a couch potato of the same height and weight.
A BMI calculation would class both of them as overweight.
That calculation is probably right for the sedentary couch potato, but not for the athlete.
The athlete's waist circumference, at 34ins, is well within "healthy weight" - if his height is 72 inches, his waist is less than half his height.
However, the sedentary person's waist of 40 inches is more than half his height.
