In the field I work in, oncology, BMI is crucial to determing how much chemotherapy to give a patient. Too much and you may unnecessarily over-toxify the person; too little and you may not be giving enough of the drug to do good.

I expect there are other fields of medicine where BMI is important like this.

So.... dosage is determined by a measurement that is known not to work for many different types of individuals? That's frightening.

No, to the contrary. The article is talking about BMI as being misused as a way to determine general health as it relates to height and weight. BMI isn't particularly good at determining "Is this guy fat, skinny or just right?"

However, BMI is a very accurate way to determine how much chemo to give a person. Weight ane height alone, or body fat measurement, would not nearly give enough information to the doctor as to how much chemo is needed.