Why BMI is often dead wrong

[Creekimp13 5,838]

if you use a BMI calculator to find out whether Arnold Schwarzenegger is at a healthy weight, you might be surprised to learn that the BMI chart considers the former Mr. Universe as obese - not only now, but when he was in the prime of his body-building career. At just over six feet tall and about 235 pounds, the younger Schwarzenegger's BMI was over 31.

So yep, Arnold himself....could get turned away by insurance companies and have his premium hiked....for his "obesity" based on an arbitrary number that has nothing to do with the reality of how much lean mass your body carries compared to fat mass.

Would it horrify you to know that the most commonly used tool to determine obesity was created by a Belgium astronomer in 1830? And that even though we have really good metabolic testing devices that can accurately measure our fat and lean stores and give a much more accurate measure of our health....we still routinely use this archaic formula?

To be fair....most of us can be fairly accurately represented with the oldschool BMI chart.

But a few of us are badly misrepresented by it. See Arnold above.

I've been a victim of the BMI chart most of my life. At 180 pounds, I was in athletic shape in my 20's. Had a washboard stomach and was doing huntseat trials (jumping horses in patterns) competitively. I'm 5' 6" and have extremely muscular legs, buttocks and arms and very broad shoulders. My husband says I'm "an Amazon warrior...not a delicate beauty". LOL. Which is a nice way of saying I'm a sturdy Czech woman.

One of the things that impressed me early on about my bariatric group was that they use a metabolic analyzer to determine our fat/lean composition and set a realistic and healthy goal weight. According to my metabolic analysis, I would have zero percent body fat at 145 pounds...the weight that would be recommended to me by a doctor using only a BMI chart. Most women my age do best with about 25% body fat....so my goal weight was set at about 170 pounds by my group using metabolic analysis. (I'm older now, so my lean mass is a bit less than my horse-flying days)

I strongly recommend metabolic analysis for figuring out goal weight, calorie goals, etc.

Human bodies are not standardized. Accuracy in measuring factual composition can be huge in developing the appropriate diet protocol for the individual.

[Rainbow_Warrior 996]

So right!

BMI is okay for about 70% of people but there are many, many people that BMI results mark as "outliers" for all sorts of different reasons.

As a 20 year old, my playing weight for RUGBY UNION was 88kg. The BMI would have been about 31 or 32 yet I was healthy and active and supplementing my R.U. with tennis, badminton and squash/racketball.

The old "life insurance companies tables" of HEALTHY WEIGHTS had ranges for small, medium and large frames and were, seemingly, more logical in determining what overweight was.

[SouthernGirl76 74]

Thanks for your post. I hate the BMI chart

[catwoman7 10,937]

one word. DEXAscan. I used that to figure out if I could afford to lose any more weight. My body fat measured 21%. Both the technician and my PCP said that was OK, but no, I should not try to lose any more weight (glad I had it because I'm certainly not near the bottom of my "normal" BMI range. Had I not known my fat percentage was getting so low, I would have kept pushing to get my weight lower...)

[Creekimp13 5,838]

My group uses MedGem Metabolism Analysis.

[catwoman7 10,937]

57 minutes ago, Creekimp13 said:

My group uses MedGem Metabolism Analysis.

that sounds like it measures RMR rather than body fat percentage - if so, the two tests (i.e., that and DEXAscan) are very different animals

I thought about having my RMR tested, but I've figured out through trial & error that my maintenance level is about 1700 kcal/day. If I go over that too many times in a week, my weight starts heading north. I'm guessing at this point, the test would pretty much tell me what I've already figured out. But it might have been helpful early on, though.

[Losebig 508]

Really interesting, I'll have to see if my group does anything like that (I doubt it). I have the same issue as I used to lift weights and have always been very active. I set my goal based on a weight I had been in the past when I lost all the excess weight, I was still considered overweight based on the charts, but at the time I was as thin as I could have gotten.

[catwoman7 10,937]

1 minute ago, Losebig said:

Really interesting, I'll have to see if my group does anything like that (I doubt it). I have the same issue as I used to lift weights and have always been very active. I set my goal based on a weight I had been in the past when I lost all the excess weight, I was still considered overweight based on the charts, but at the time I was as thin as I could have gotten.

if your group doesn't do it (this is the first time I've heard of one that does, but maybe it's just never come up before), there are commercial outfits that do them. In fact, some of the DEXAscan places do RMR tests for an additional cost. Sometimes you can get both done through university sports facilities for a reasonable cost - although not always. The university I work at charges the same for a DEXAscan as the commercial outfits do (I don't know if they offer RMR tests - I've never checked into it. But I know people from forums who have had both done at the same place)

[Losebig 508]

8 minutes ago, catwoman7 said:

if your group doesn't do it (this is the first time I've heard of one that does, but maybe it's just never come up before), there are commercial outfits that do them. In fact, some of the DEXAscan places do RMR tests for an additional cost. Sometimes you can get both done through university sports facilities for a reasonable cost - although not always. The university I work at charges the same for a DEXAscan as the commercial outfits do (I don't know if they offer RMR tests - I've never checked into it. But I know people from forums who have had both done at the same place)

Thanks!!!!

[ShelterDog64 2,364]

I've had both RMR and Air Displacement Plethysmograph (ADP) testing done as part of my pre-op pathway. The RMR was way off, IMO, as it said that my rate was sufficient to support almost 3000 cals/day. What???? The ADP, otoh, was very realistic as I have a somewhat lower body fat number for my height and weight.
I hate the BMI charts...they all say my sweet spot is right around 140 lbs. I can't imagine being 145, I wasn't that light when I was in the Army, training daily and 20-something years old. I'm at about 165, wearing a size 8 at 53 years old and it's really close to an ideal weight for me. I wouldn't mind losing about 5 more, but I'd be too thin at 140.
My surgeon isn't hung up on BMI...he's all about getting off BP meds, lowering your hA1c, being able to move more, feeling better, liking your appearance more. He says that every pound lost is a step in the right direction and that we should all embrace our individual differences. I saw him at a social event a couple of weeks ago and he told me that he barely recognized me...until he saw me smile, then he knew who I was. That made me SO happy