I’m calling BS on BMI


You can see by the title of this post what I think about BMI. Let me explain.

Right now, I’m nearing peak physical condition for me. Not to say that it’s all that impressive, but I’ve dropped 20 pounds since moving to Tulsa two years ago. I can squat nearly twice my body weight. And those once-tight (like poured-into tight) 32-waist jeans need a belt now.

Some other things: As of Monday, I’m at 15.3% body fat, down about 3% since last fall. Not amazing, and I won’t be an underwear model anytime soon. But for someone my age, it’s well within the healthy range. In fact, it’s well within that range for men in the next youngest bracket.

Fitness-wise, I’m running at a level somewhere between half-marathon and marathon level. Again, not that impressive, but I’d consider that decent enough.

And my BMI is 25.7.

BMI, or Body Mass Index, records 18.5 to 24.9 as being normal; 25-29.9 as overweight; and 30 or more as obese.

I need to drop another 6 pounds to be on BMI’s edge of normal/overweight.

Wrestlers, boxers, football players and many other athletes my height but with greater muscle mass would blow past my marginal reading and be full-fledged overweight, and maybe even obese by BMI standards, even if they were at 10% body fat and could deadlift a truck.

So I’m just going to go out and say it: BMI is bunk. It’s past being a flawed tool of measurement. It’s fatally flawed. If someone is going to tell me that a chain-smoking, no-muscle-tone couch jockey who happens to be my height but weighs 6 pounds less than me is the healthier man (which is what BMI implies with its labeling), well, that’s ludicrous.

And in a time where body image among many is a significant issue (think adolescents and many women), the ramifications are even more important.

If we’re going to use BMI, it needs to be changed. Recalibrated. Figured in a way that accounts for more than just weight and height. As it stands now, it’s a tool so blunt that it’s not worth using at all.

Bob Doucette

On Twitter @RMHigh7088


14 thoughts on “I’m calling BS on BMI

  1. BMI is the medical community’s attempt at trying to justify higher insurance rates for their patients…most doctors don’t know dick about Fitness in the first place so they go with this BS…Great title!!!

    • Thanks for the word, dude! Yes, I agree. I think a lot of health professionals fall back on BMI the same way they fall back on prescribing medicines — it’s what they’re taught to do in school, and instead of looking at someone in a holistic manner, they just plug in facts and figures to spit out a result/cure. BMI is a bad tool. It needs an overhaul.

  2. As someone learning in the health profession, I’ll throw in my two cents.

    They do it because it’s fast. Doctors have to average 15-20 minutes for a normal patient visit, you have to save time anywhere you can. Taking proper body-fat measures takes time, training, and even then they’re still prone to being inaccurate, based on the skill of the person taking them and the limitations of the tools. So they use BMI, which will be somewhat accurate for the general population, but inaccurate for fit individuals or the elderly.

    For what it was meant for, BMI isn’t bad in itself. BMI was never meant to be a measure of individual health, it was devised to estimate the health of a population as a whole. When using it for that, it’s not that bad. But there are far too many different body types for something like BMI to be accurate for every individual.

    • I appreciate your comments, and I can understand that. But I think BMI needs some changes. The medical community could stand to do some work here to make that happen. As it stands, it’s not a good tool.

      • To me, that’s sort of like saying that we need to change hammers so they can do the job of screwdrivers. There’s not really any amount of changes that will make BMI good for individuals, because it was never designed for it. What needs to be changed is the medical community, either a new tool that works for individuals should be developed or they should learn to take more time to a proper physical assessment.

      • The problem with that line of thinking is thus: In order to measure a group, you have to measure individuals. And if your method of measuring individuals is flawed (and BMI is clearly flawed), then the measurement of the group is flawed. Yes, we need the practitioners to change. The use of BMI is a lot like the use of prescription drugs — a quick, general answer to hastily diagnosed problems, and it often falls short. So that needs to change. But if we don’t give physicians or health practitioners the correct tools, they’ll keep giving us faulty analyses.

      • It really depends on what you’re trying to do. The fact is, any method that’s accurate for measuring individuals is going to be impossible to use on a wide scale, because it’d require that you measure each individual, which you can’t do for a large population. BMI is meant to be a rough guess and that’s more feasible when trying to measure large groups than, say, trying to take body fat percentage of 30,000 people. If anything is to change, I think tweaking the numbers up a little would get you a little more accurate numbers, but I’m not sure if that’s right.

        As far as large groups go, it’s just impossible to take every body type into account, even for an individual measure. Any measure that’s accurate for a 20-year-old couch potato is going to be inaccurate for an NFL player and for an elderly individual. There are dozens of ways to measure fitness and they all work best on the particular populations they were created for. BMI is a blunt tool meant to try to get the average right, and that’s really all you can expect when trying to determine, say, how fit Houston citizens are compared to London citizens. It just got incorrectly co-opted by insurers and doctors.

  3. From what I can tell (at least in my medical school) it is emphasized that BMI is not the accurate estimate. We are taught that it will give us a rough estimate, but to never consider a number without the context of the patient. If we have a patient with a normal BMI but a very uneven weight distribution (being particularly hefty around the middle) then we know that the person isn’t healthy. Similarly, if we have an athlete with an “overweight” BMI, we aren’t taught to treat them as overweight.

    Point is- you are totally right. But also, I don’t think the estimated BMI value is really taken into consideration without the entire context. Possibly I’m just naive as I’m not really in the healthcare workforce yet!

    • Good word. Where I have a problem with BMI is how it is used in either 1) patient/client evaluation and 2) general public information dissemination. Like I said, it’s an impossibly blunt tool to be used at face value, and therefore needs changes to make it more useful not only for the health professional, but for the patient/client. And as far as public information, that’s really where it falls flat. Especially in populations with body image problems, having them target BMI-based goals seems particularly unhelpful. And you’d be surprised at how many people outside of the fitness industry but within health just fall back on it as a default.

      And then, worst of all, that gives insurers carte blanche to set rates based on screwed up figures. So there is that as well.

      I’d like to see someone with medical academia come up with something new and improved. Lord knows we’ve had enough food pyramids and such to go around.

  4. Pingback: Here’s Hoping I Don’t Hit 29 | Roof Pig! Most Unexpected.

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