First, I was surprised that the BMI calculation was almost 200 years old! Its surprising that nothing better has since been introduced.
Second, I was surprised that it became well used because of insurance companies. Maybe this shouldn't surprise me? Actuaries are in the business of determining "who should pay more for insurance" so this really falls into their comfort zone.
Third, I was surprised that I never realized that the US reduced the % in the late 90s. I always knew that the number of people considered obese/overweight jumped considerably in the last few decades. But, then again, I knew that everyone blamed the food and lack of exercise... I never once heard what the adjusted figures were for prior decades. Wouldn't we like to know the "apples to apples" comparison? Did they really jump, if you adjusted the numbers to ensure proper comparisons?
[Via: BMICalculator.org BMI Calculator]