Ordinarily the WL blogosphere and I are just one big basket of snuggles, with deeply similar opinions on most topics. But there's one where I am apparently a renegade, which is the subject of Chunky Monkey Mamma's intriguing blog post over on Cranky Fitness (see my sidebar, sparing me the labor of making a link).
The opinion as expressed by the majority is that BMI is complete horseshit, and should not be measured at schools or conveyed to parents.
My thought is, it's all information, right? There's "Your hemoglobin is 9.3" and "I saw your husband clinching a redhead in the Denny's parking lot." Most people seem to feel that telling parents about their kid's BMI belongs in the latter camp, Information That Does More Harm Than Good.
Since it's my blog, this is my take on it. Pull up a chair.
What is BMI? It's just a fancy measure of weight versus height. We do it all the time when we look at someone's blog stats-- they weigh 173 pounds, for example. We look to see if they're 5'1, 5'8 or 6'1. If they're 6'1" and 173 pounds we stop reading their blog in annoyance because damn it, this isn't a proper WL blog, they're not even fat. See? BMI in action.
Most of us know that BMI doesn't measure body fat or muscle mass or athleticism. But it does take a stab at measuring. And the majority opinion seems to be saying that because it's not a perfect measure, we shouldn't take it or communicate it. They don't want to know, they don't want the kids to know, because it's upsetting.
The thing is-- if my doctor takes my fasting blood sugar and it's 113, it's very upsetting. I'll be worried and possibly even pissed at my doctor. Does that mean she shouldn't tell me? In my case, that measure had a very real and helpful impact on my behavior. It's possible, seeing objective evidence that a child's weight for height is unusually high, a parent might investigate further and possibly make some changes at home.
I'm not afraid of a number. Well, okay, some numbers, but not that one. BMI may be flawed (it is) but it is widely accepted, used by everything from the World Health Organization to research studies to insurance companies to Weight Watchers. Not forgetting weight loss bloggers. My kids tell me height and weight is taken privately: no one sees the letter except for the school nurse and the child's parents. Our letters actually take pains to describe the limitations of BMI. How the parents use that information is up to them, just like any other measure including grades, test scores, or vision screening results.
If this were any other number, like cholesterol or nearsightedness, we wouldn't be pitching fits over flaws in the system of measurement. It's because body weight is such a wretchedly loaded topic people don't want to know and some even get angry if a potential problem is mentioned. My doctor never said a word about my weight at any point, even with fasting blood sugars over 100. I'm sure she's been conditioned not to. Is she really doing me a favor? What do you think?