Is the Body Mass Index a crock?

Factual Questions
1

OK, so I’m back into workout mode. I’m following a definitely not high impact aerobic program, half an hour a day. Also, I’m eating healthy, low fat, whole grains, lots of fresh fruits and veggies.

I’m wondering about this BMI thingy, though. According to the BMI, at 5’2", I should weigh somewhere between 120-136 lbs. I say bullshit. My ideal weight, I think, is somewhere between 130-136, which, according to the BMI, would be on the high end of normal, as in I probably should think of losing a few pounds. I can carry as much as 140 and still look good in a midriff baring blouse, provided I stick with my workout and keep my abs and obliques in shape. (I’m currenty 15lbs, defnitely overweight, but not anything approachig obese.)

I think there’s a lot the BMI doesn’t take into account. Body build, for one. I have a pretty hefty skeletal frame- broad in the hips and shoulders. If my weight drops below 125 (some people have told me that 120 would be about right for my height), I start to look bony. Bony is not pretty. I also start losing weight in places I want to keep it, like off my bustline.

Which brings me to another point. I’m packing a set of D-Cups, which means that a higher percentage of my body weight, even if the rest of me were quite slim, would still be fat, because breast tissue is mostly fat. If I get down to my ideal weight, I’ll still probably be a C or D cup. If my weight drops too much, the girls start to look like a couple of underfilled bags of skin (no joke, I was down to 118 at one time, and the girls did not look happy at all) I figure with good pectoral exercises, they can still look firm even if I lose a cup size, but no more than one cup size.

Also, I have a fairly large butt, which, even when I’m overweight, is still mostly muscle. Even if I get the spare fat off my butt and hips, I’m still carrying a lot of weight in that area. But, as I said, that weight is mostly muscle, and muscle is denser, thus heavier than fat.

So, is the BMI really a valid guideline for what a person’s weight/heght ratio should be, or do we need to come up with something that takes into account things like general build, breast size, etc.

Or has someone already done it? I’ve done a couple of searches on the subject, but the standard BMI is all I can come up with.

2

The main problem with the BMI is that muscle weighs more than fat. So, you can have two people with the same height, and same weight, (and therefore the same BMI) but one of them is a weight lifter and the other makes a couch potato look active. Guess which one is in better health (all else being equal, that is: no hidden surprises).

Usually I’ve been told that using determining your body fat percentage and combining that with other methods is more accurate to determine overall ‘health’.

And, I’ve always felt that we females should be able to subtract the weight of our breasts from our total weight, etc. I may weigh cough, but I’m skinner than one of my friends who’s the same height and weight… because of my ample bosom. As an add on to Thea Logica’s question: does anyone know why this isn’t done? (The subtracting of the breasts from the weight, that is.) And why we wouldn’t want to do things this way, if it isn’t being done?

<< BATCH - A group, kinda like a herd. >>

3

From a layman’s totally non-medical POV, I suspect it’s a crock. I went to the doctor about six months ago, and was weighed and measured. Now I am a Big Guy[sup]TM[/sup]. I’m close to 6’5", and I’m more of your footballer’s frame than your basketball player’s one. I weigh in at about 265 pounds (I’m translating for you 'merkins, so I hope I’ve gotten it right).

The thing is, I’m first to admit I’m a bit overweight. I don’t exercise much, and I love a beer or two. But I have a very slight beer belly. It’s borderline whether it’s noticeable or not when people meet me. Only family and friends can see I’m slightly heavier than I was. The rest of my body has no areas of flab. In all honesty, I reckon losing 25 pounds would be about right for my own optimum weight. I’d still be a big guy.

And the doctor told me (based on the BMI) that I was borderline obese??? WTF?

If I’m really fat, I’ll admit it. But I know I’m not. I think it’s a flawed system.

4

I found this article discussing different measures of obesity. Of the methods they tested (including BMI), multiple skin fold-measurements were most predictive of “true” obesity.
The most you could say about BMI is that it’s convenient (easily determined) and reliable to a degree. You could probable make a statement like (I’m making up some of these numbers)," A BMI of 30 or greater includes 95% of reproductive-age women with a total body fat percentage deemed harmful by current medical practice. 3% of reproductive-age women with a BMI>30, do not have a total percent body fat likely to do them harm."

If you reduce the BMI cutoff to 25 then you include a greater percentage of truly obese women (enhanced sensitivity) but also include more non-obese women in the group (reduced specificity).

If you feel good and look fit, I wouldn’t sweat the numbers

5

According to the CDC, it’s a useful measure.

6

BMI works well for most people. It is a mistake to apply it as a discriminant between healthy and at-risk people, but it can give you a rough idea of where you are.

Your weight and body fat percentage would be a better measure, but BMI is easier to calculate.

7

I think it’s a crock. My bony-as-hell, skinny, “You need some more food, sugar” girlfriend just barely makes it into the “normal” range.

8

I think it’s a crock as well.

I’m 5’5" and built like you, Thea. Big knockers and a big skeletal frame. The most I’m “supposed” to weigh is like, in the 140’s. I’d look anorexic!

My goal is to get to 165, which will put me in the “Overweight” category. Coming from my all-time highest weight, though, that’s fine with me. Screw 'em.

9

Thing is with DarrenS’s link the most telling words are “general population”. You’re comparing yourself to the average person, but what if you don’t fit into that?

See with me I am 6’1 and weigh around 200lbs (give or take a few, on a good day, before I was pregnant) I can admit to needing to lose about maybe 25lbs, if that. I’d probably be good with a little less. According to BMI I am bordering on morbidly obese. This does not take into account my bosom, the fact that I am big boned and am more or less muscle (I admit to having some flab but it’s not too bad). I’m built more like a guy, rather than a tall supermodel type. I’ve always felt BMI to be a bit of a crock, it may work for the average person but when you start getting to the outsides of that it doesn’t work.

10

There are a couple of past threads on this with good answers, search on “body mass index” or BMI in title.

11

Good luck searching for ‘BMI’ on here :wink:

12

I think that would really only work if you took into account breast size. If you’re a D-Cup, your body fat percentage is going to be quite a bit higher than the next chick over with two fried eggs on her chest, all other factors being equal.

13

I think you’re being overly conservative. If you’re in the normal range, you do not need to think about losing a few pounds. That’s what the normal range means. But even so, I agree that it’s best as a guideline.

You should check your BMI again. I’m also 6’1" and 200 lbs. This gives you a BMI of 26.4, which is on the low end of overweight. Whoever told you it was anywhere near morbidly obese was either being alarmist, or they didn’t understand the scale. Obese doesn’t start until 30 or so.

14

I’m sorry… I forgot that that was what it said last time I checked it. Before I lost a bunch of weight, but even then the one given me was 29 and the literature given me by people* said it was obese. (Okay not morbidly I’m mixing things up in my mind here, I seem to remember as the stuff I had about BMI saying that.)

[sub]*This was at a woman’s show where they had this thing that tells you your BMI exactly. Tells your weight and height and then they give out info about losing weight, how much weight is bad etc. I think it was Capital Health run, but I could be wrong.[/sub]

15

Umm, girls, breasts have lots of fat, and it counts just as much there as in any other part of the body. Nice try though :slight_smile:

If I don’t count my stomach, my BMI’s fine too!

16

I used to think it was a crock. Now that I’ve been haning out in the gym I’ve come to realize most people are A LOT fatter than they think. Weight has nothing to do with fat. I am now 6’ 183#. I have a 45" Chest and a 32" waist. This is what I SHOULD BE. And quite frankly it is correct.

Look at your body truly. If you are 6’ you should be a 32 waist. Not in jeans in dress pants. Is your stomach over your belt. You’re fat then. I know people that are 6’ 190 with a 36" waist. Come on that is fat.

Can you see your stomach? You should be able to. I recently red in GQ “The Rock” has 2% bodyfat? Come on the guy would be basically a skeleton with a skin and muscle draped over him.

But that isn’t a bad thing. But truthfully, you should be able to see your muscles. So your a little fat big deal. But even getting down to a number within the body mass isn’t so great. What if your stomach still hangs over your belt? Are you thin just cause your BMI says so? No. How many of us know men who are basically thin but look like they are pregnent.

I read in Newsweek recently. 55% of all people OVERESTIMATE the number of calories consumed in a day. 25% of all nutritionists (who should know) also overestimated.

We all think we need far more food and far less exercise than we really do.

The BMI if you really look at it (and I used to be a disbeliever too) is reasonable. Unless you are a professional bodybuilder or using steriods it is reasonable. It isn’t muscle for most people if not virtually all. Remember when you carry more fat you also carry more muscle as something needs to drag that fat around.

17

I have a BMI of 26 which makes me “overweight”.

Yeah, right.

No, my gut does NOT hang “over my belt”. My waist is 28 - just as it’s been since high school. That makes me a 36-28-38. That’s not overweight, that’s female.

And, as a matter of fact, I do have muscle definition in my arms and legs.

Screw the numbers. They don’t fit everyone.

Yeah, if you’re a 35 or 40 you have a problem - but the lower edge of “overweight” on that scale is catching a lot of folks who aren’t fat.

18

How tall are you? You could still be overweight with a 28 waist.

19

I think some people fail to realise you can be overweight without being grossly overweight, and you should still try to lose a bit.

20

Yes that would put you in the overweight category and rightly so. I’m 6ft1 and weight about that. I do taekwon-do twice a week and play soccer once a week. I’m right in the middle of the normal zone for my height, there’s no way 165 is normal for you.

Some of you people need to stop kidding yourselves.