More on the BMI

Last week, I aired my feelings about the BMI as a measurement tool for us and our doctors. I’m not done yet. I stumbled upon a podcast called “Maintenance Phase”, presented by Aubrey Gordon and Michael Hobbes, which discusses the shortcomings of the wellness industry (if I’m being kind, as ‘criminality’ is probably more accurate than ‘shortcomings’). You might wonder why I’m broadening the scope of a simple personal trainer’s blog to deal with the industry, and I’ll tell you why: I’m part of it. So it’s on me to make sure I keep my personal scope of practice evidence-based, scientific, and always critical of trends, fads, etc.

Anyway, back to the BMI – what I learned from the podcast episode is that not only is the BMI not appropriate for assessing individual health, when you are classified as having a high BMI, you may experience worse medical interventions. Once we have a vicious cycle set up between a high BMI causing medical professionals to assume weight loss is a necessary intervention, then the failure to achieve weight loss becomes how you personally have failed to participate in your care. This is a big monkey wrench in the path to getting better from whatever the hell is actually wrong with you. Using the BMI as a primary marker also messes with average and thin individuals, because they are not always monitored as closely on the conditions that are currently associated with obesity. I can share two stories about this.

I bring mine up a lot because of how ridiculous it was: I had undiagnosed IBS and kidney disease as a teen, but I was FIVE POUNDS over ‘ideal’ on the height-weight chart, so my doctor “prescribed” losing those five pounds. (I did, it didn’t change a damn thing.) My friend Julie is in a group of survivors of SCAD (Sudden Coronary Artery Dissection, a very dangerous type of heart attack). She was thin, active, and walking around with a time bomb in her chest, because she was not assessed on risk factors, but on the standard metrics of heart disease, which are mostly there to rapidly identify heart attack potential in men.

What are those standard metrics? Blood pressure, cholesterol, heart rate….and BMI. In both of our stories, BMI is a meaningless number that added nothing to our care.

So why do we use it? Because we don’t challenge it, and we actually should. Because we think about ideas like
“ideal weight”, and right in that concept, we subconsciously draw a ceiling where the BMI number puts us, whether that’s accurate or not.

Ok. Now, let’s just call the BMI trash. If you’re someone who wants to find out their ideal weight in order to create goals for being generally healthier, let’s sketch that out. A healthy weight generally means the point where you can move easily, sleep well, feel energetic, have good-to-excellent blood pressure/blood sugar/cholesterol through diet and fitness alone. Sounds good, right? Let’s just do that! We’ll all be thin and soooooo healthy!

Not so fast.

I have friends who are considered 100+ pounds “overweight”, and yet are all of the things I just described. Their serum cholesterol is better than mine, and so is their blood pressure. Because BMI doesn’t really tell you meaningful things. And it wasn’t ever intended to. It was meant to be a way of looking at an entire population, to find an average size. It’s simply not a tool for health. It is misdirection, and has us looking in the wrong direction. We’re not cogs produced in a factory, where a single measurement can identify if we’re faulty or not. It’s not that simple.

It’s a complicated world that we live in. Everyone wants easy answers, somewhere to struggle less with the ambiguity of it all. So I’m going to put my personal trainer hat back on and say: “Exercise because we are animals, and all animals need exercise. Find something you love to do, preferably outdoors, and do it every day. Eat because you’re hungry, and aim for the most basic, unprocessed forms of foods that you can find. Get enough protein. Get enough sleep.”

Everything else on top of that is just….marketing.