For some time now, I’ve wanted to talk about the Body Mass Index (BMI), and last week a little nugget fell into my lap. I stumbled across an article in MacLean’s about a new measure being proposed by some obesity experts. Enter the Edmonton Obesity Staging System. What this measure does (that the BMI cannot) is take into account that not every obese person is at equal risk for weight-related diseases, even at the same BMI. In fact, it even allows for the novel idea that an obese person might be relatively healthy.
In the article, the following example is used to demonstrate how the same BMI means different things for different people: “Two people…One is a young woman, aged 24, who seems relatively healthy and plays soccer on weekends. The other is a large 32-year old man who suffers from hypertension and sleep apnea. The woman is five foot five, about 190lbs; the man is six feet tall, 265lb…both are ‘obese’ with a Body Mass Index of 30 or more.”
As the article goes on to explain, it doesn’t take much to ascertain that the only thing that these two people share is a BMI. Any potential medical intervention is going to look very different in each case and using the same approach for two people with such different lifestyles and symptoms would be silly. However, many practitioners are without a sensible guide and have only the BMI and its attendant diagnoses at their disposal when dealing with obese patients.
It seems like a measure as unrelated to specific information as the BMI leaves much to be desired. Yet, in a Frontline diet documentary mentioned in my third post, a nutritionist, going on host Stephen Talbot’s BMI alone, lists off (with a straight face) an array of horrible health risk factors: heart disease, stroke, osteo-arthritis, high cholesterol, adult onset diabetes and some types of cancer. The good doctor planned to check Talbot’s cholesterol and to do a blood glucose test to ensure that he wasn’t “already diabetic,” but all of her declarations were based on just his BMI. At 5’11’ and 210lbs, Talbot had a BMI of 29, which put him in the overweight category, edging dangerously close to obesity. Ironically, he hadn’t considered himself overweight at all prior to that day.
I’d like to believe that most nutritionists would run a few more tests before declaring that you were about to contract any number of terrifying diseases. It’s telling, though, that this nutritionist talked about using the BMI “a lot more” these days and seemed content to be seen on television making a lot of conclusions based on that information alone. I’m left wondering, if Talbot had been a naturally thinner man, with deceptively high metabolism and a normal range BMI, would the good doctor have bothered to ensure that he wasn’t “already diabetic?”
I have a great family doctor who doesn’t treat me like my size is the only thing that defines me. Knowing my 30+ BMI full well, she refers to me as “not that overweight.” Not every overweight person is blessed with a doctor like mine though; a system like this is a great way to begin and facilitate conversation between patients and doctors, so that interventions are tailored to the individual in question. Clearly the one-size-fits-all-BMI approach hasn’t worked thus far—this new kind of thinking is long overdue. My favorite quote in the article, from Dr. Arya of the Canadian Obesity Network, highlights something that I think we all know, but that most people don’t like to admit: “Size is health in many people’s minds, but it shouldn’t be.”
I’ll second that emotion.
To read the full MacLean’s article, click here. For more information on the Edmonton Obesity Staging System, check out Dr. Sharma’s blog.
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