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Body Mass Index

Holland Clinic BMI Checker

Body mass index or BMI is very old calculation that has become one of the most popular and oft-used measures of human body weight. The very simple definition of BMI is: 


BMI = (Body Weight in Kilograms) % {(Body Height in meters) x (Body Height In 
Meters)}


Since we use imperial measurements in the United States, the formula is simpler as:

BMI = {(Body Weight in pounds) x 703} % {(height in inches) x (height in inches)}

So, for a woman weighing 230 pounds and standing five foot six inches tall, her BMI would be about 37 which is considered dangerously obese. 

The problem is that after all the fancy calculations are performed and the pretty graphs are drawn, BMI is only based upon two measurements: height and weight. BMI does not account for gender, for muscularity, for bone structure or for body fat measurements. In the end, BMI is just another height versus weight chart like those that life insurance companies have used since the 1930s. Here is an example of the problem with BMI: a 26 year-old male football player might weigh 230 pounds, stand five foot ten inches tall and have a BMI of 33 and be in superb health because his weight is muscle not fat. On the other hand, a sedentary woman of 52 who is five foot six and weights 145 pounds has a BMI of 23.4 but might be quite unhealthy because she has very little muscle. So the problem is that just knowing a person's height and weight doesn't tell us what we really want to know, and that is how fat he or she is and how much risk that places upon the person's health.
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