Wednesday, February 10, 2010

BMI BS


In light of my recent post on fat people and America’s misguided attempts to “fix” the obesity problem, I’ve been thinking about one of the measures of being overweight, the Body Mass Index. It’s one of the most widely used and quickest/easiest ways to determine where someone falls on the fat to skinny spectrum. BMI is measured by calculating your weight against your height. The problem is, that’s all it measures- it is a very imperfect system that’s too widely used. In fact, Michelle Obama, in talking about her childhood obesity plan, cited that her family doctor cautioned that her daughter was overweight based on her BMI.


To give you a sense, I am 5ft 1in tall and weigh 110 pounds, my BMI is 20.8 (right in the middle of “normal” weight), but I could be as skinny as 98 pounds and still be considered “normal” (not underweight). If I was tipping the scales at a whopping 133, however I’d be considered “overweight.” Many take offence to the fact that there are two classifications for fat and only one for skinny. I take offence to the following:


BMI doesn’t take into account body fat or muscle. It also doesn’t take into account diet and exercise, or family history. There are plenty of unhealthy sedentary skinny people who eat nothing but junk food. While conversely there are plenty of healthy people with a predisposition to be larger than “normal” who are active and eat well.


Which is why it’s surprising the a company like Whole Foods would use employees BMI (along with better measurements such as low blood pressure, and not smoking) as a measure of healthiness and subsequently size of employee discount. The idea program of course is to encourage the employees to be healthier thus costing the company less in insurance costs. But shouldn’t a Giant Health Food Store give larger discounts to those that are the least healthy? Making those $10 strawberries affordable?


For a great illustration on just how crazy pants BMI classification is, check out Kate Harding’s BMI slideshow of women of various sizes with their BMI classification next to their pictures.


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