Dat BMI thing seems to be wrong


#1

http://www.npr.org/templates/story/story.php?storyId=106268439


#2

yeah, BMI is horribly inaccurate, this is well known. Its just… easy to calculate


#3

Bro science, GOOOOOO!


#4

I’ve heard of stupid stories like police officers being suspended as “not physically fit for duty” because their BMI was too high… never mind that the officer is a bodybuilder with hardly any body fat.


#5

Weight on the whole is just plain the wrong metric for what most people really want, which is to alter the way they look. But scales are a helluvalot more convenient than tape measures and notebooks…


#6

I agree that BMI is bogus, but only when taken as a be-all end-all to fitness.

I have a high BMI. Take a look at me and you will see that I have too much fat around my midsection. BMI is an indicator, not the final word. I have known body builders who were obese by the BMI, but had 4% body fat (which is probably too low if anything).

It should be pretty easy to look at the BMI, body fat percentage, and use your eyeballs to determine if someone’s weight is unhealthy. No single indicator works in isolation (except maybe body fat). I hide my weight well, but my BMI does not lie. My body fat percentage puts the nail in the coffin that I am over-fat.


#7

A close friend of mine in the military has this issue.

As a 30+ year old, he has no problem meeting the standard of fitness for an 18 year old, but his weight is juuuuust under the limit of what they consider acceptable. So because he is short and stocky rather than tall and wiry, he could get kicked out of the service.

Ridiculous.
No reason dwarves and elves can’t fight side by side!


#8

As with many things, BMI is a handy guide, but common sense should be applied.

If your BMI says you’re morbidly obese and you look like a hippo, it’s probably accurate. But if you know your BMI is wrong because you have high muscle density, then just ignore it.

It’s basically for normal people, who want to know if they should eat less and do a bit of exercise (hint: yes), not the body hacker community.

Using it as an absolute parameter for anything is just daft.


#9

But even this is not necessarily true. BMI measures the ratio between two semi-dependent variables, neither one of which is definitively correlated with health. Unless you are, in fact, in the morbidly obese category (and sometimes even then), the other measurable health statistics such as serum cholesterol levels, blood pressure, and the like are a FAR better fit to health than the fact that I happen to have a slow metabolism (and therefor fat) while still being physically fit.

Conversely, I was friends for years with a guy who ate nothing but junk food but looked like a body builder in coke-bottle glasses and a scraggly beard. Not a pound of fat on his body, not a minute of exercise.


#10

My understanding was that the BMI was developed as a means for analysis of large population groups, but really doesn’t apply for individuals whatsoever.


#11

my BMI said I was obese, but anyone looking at me would say I was slightly overweight, if that. One coworker burst out laughing when I said my BMI indicated I am obese. It just seems to me that if it is so horribly inaccurate for any given individual, what says it is good for large population groups? You might look at ancient sparta, see that everone has a highly-muscular, fit, warriors body, and proclaim they have a high BMI and are overweight. You can easily select a large-but-biased group to analyze and get nonsense results because you don’t have people erring in the opposite direction.


#12

Yep, true points. This is why I just plain ignore the BMI, always have. In fact weight in general I mostly ignore, except that it’s so bloody convenient as a metric to track.


#13

I’d guess the proportion of genuinely overweight people compared to the athletes was significant enough for BMI to be useful at a population level.

If someone had invented the BMI in Sparta, the numbers would likely have been very different. I assume the current numbers are for modern-day first-world slobs, mainly.


#14

Wouldn’t that just reinforce the point? We have a metric that tells us we are overweight because it was calibrated to tell us we are overweight? We are constantly being told we have an obesity epidemic, calculated from BMI, which is somehow including every athlete and bodybuilder in with the obese. I would have been boosting those numbers.Tall people also tend to score higher than you would think. All of these, just boosting the obese category, because it seemed like most people with that ratio were overweight. It seems silly to be using a metric that couldn’t distinguish between a body-building fad and free McDonald meals for everyone.


#15

According to the BMI calculator here, I have a BMI of 35.9. I know I need to lose some weight (6"2, about 275-280 lbs) but I’m not obese (Yes, I am overweight, and that’s one reason why Soylent is so interesting). I just have a really heavy build- I’m a big guy.


#16

I’m a 5’ 11" 44 year old male and weigh 185 that makes my BMI 25.8 which is slightly overweight. I don’t think I’m overweight, when I was in even better shape my BMI was higher - it’s just a worthless indicator for individual health :frowning:


#17

Will something like a ‘BFI’ thing be more accurate? I am curious.