# is BMI accurate?



## the-royal-mail (Dec 11, 2009)

I recently read a comment online that stated BMI was not an accurate measurement of obesity. The example given was a 5'11" man, said to be obese at 220lbs.

I don't consider myself obese and if you saw my body you wouldn't say I am. According to BMI I am about 25 lbs in the overweight scale. If I lose those lbs I will be "normal weight".

What do you guys think - is BMI the best way of establishing ideal weight goals or is it oversimplified?


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## marina628 (Dec 14, 2010)

For most people it is accurate but i know a 5'6 man who is 215-220 pounds , he works out an all muscle.I like the pinch test myself ,anything more than an inch or two on the belly you are fat.BTW I am fat but working on it lol


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## jamesbe (May 8, 2010)

As marina said, BMI isn't the greatest because it doesn't take into account a lot of factors the biggest being muscle.

But for most average people it's pretty good. My idea BMI is 145 - 150 lbs. I was 180 for awhile and when I went back to 150 I felt much better. I am back up to 155-160 and now I feel fat again.


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## MoneyGal (Apr 24, 2009)

It is only reflective of two measures: height and weight. 

I do a lot of body composition testing - right now I have the results of a DEXA scan, bioelectrical impedence test, tape measure (measures girth at given points), and caliper skinfold measurements.

(Some people obsess about finance and trading. My obsessions lie in a different direction...)

My BMI is high and it is "accurate" in that it is accurately measuring what it measures. But I am a weightlifter and much more muscular than the "average" woman (apparently; that's what my most recent impedence tests say, because they measure against an average). So my bodyfat measurement does not put me in the "obese" or even "overweight" category, although my BMI is "high." 

Many weightlifters have this same issue. Luckily, if you measure progress by means other than BMI, you don't care.


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## MoneyGal (Apr 24, 2009)

Also - I'm sure you realize this, but "obese" and "overweight" are different categories. It isn't clear from your original post that you are making the distinction. 

I also wonder, honestly, if we as a society have lost our sense of what "normal weight" is - and whether we (not speaking specifically to you, TRM) now think of "normal weight" people as "skinny."


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## the-royal-mail (Dec 11, 2009)

Interesting replies!

Yes, I was aware that overweight and obese were two different categories.

You make a good point about muscle weight due to body building/exercise and I don't dispute it. I would just caution that some people use that as an excuse to discard BMI results based on the size of their frame or other factors.

I personally kind of like the BMI index and it does seem to be accurate in my case. I think if I lost those extra 25 lbs and put myself in the normal weight category that would be great. Last year I lost 45 lbs so I know I could do it if I had to but as things stand now I actually feel and look ok.

I started this thread because I've heard a lot of people who were opposed to BMI and thought that was going a little overboard. It's only a guide and given our junk food and obesity epidemic, we should really be using a guide to get ourselves back in healthy weight ranges. That would solve so many health issues that plague so many people these days and costs the healthcare system a lot of money.


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## Abha (Jun 26, 2011)

This is pretty cool for those of you interested. It was a photoshoot where different athletes posed together to show their differing heights and weights but the constant theme was they were all athletes (probably really good ones) at their individual sports.

http://ninamatsumoto.wordpress.com/2010/12/18/athletic-body-diversity-reference-for-artists/


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## Four Pillars (Apr 5, 2009)

How do you figure out your BMI?


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## MoneyGal (Apr 24, 2009)

There's a million calculators out there, but BMI = your body weight divided by the square of your height.


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## jamesbe (May 8, 2010)

MoneyGal said:


> I also wonder, honestly, if we as a society have lost our sense of what "normal weight" is - and whether we (not speaking specifically to you, TRM) now think of "normal weight" people as "skinny."


YES YES YES For sure!

Go to Europe lately? Everytime I have been I have been amazed how almost everyone is "skinny" but really they are just normal weight. Sure there are overweight people in Europe but it seems like less so than in NA.


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## ddkay (Nov 20, 2010)

That's a cool photo series Abha.

Hollywood people go through extreme transformations, e.g. Christian Bale in The Machinist vs Dark Knight vs The Fighter. Swinging up and down hundreds of pounds can't be that good for you. :S

My ideal BMI is 20 +/- 1, right now I'm 6'1" and 155. I can add or lose pretty quickly... I usually lose "lumpiness" with temporary calorie deficits and cardio. It's a little different for everyone though. Gaining is too easy, I don't even have to change my diet, just sitting multiple hours a day takes care of it...


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## MoneyGal (Apr 24, 2009)

That NYTimes photo series is pretty famous. Here's another one:

http://espn.go.com/espn/photos/gallery/_/id/7030506/bodies-want-2011#1

Check out the woman who is 6'6" and 200 lbs of pure muscle.


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## KaeJS (Sep 28, 2010)

BMI is a guideline, it is not the rule.

Like mutual funds, it is a good place to start, but its not the best.

You really have to look in the mirror and determine what weight is your ideal weight.

TRM, I am also 5'11, but I am 181lbs at present and I am working my way down to 165.

My mom thinks I am too skinny at 181lbs, but it's all about perspective. Some people are fine with a gut, some people don't care.

I don't care about a 6 pack or anything like that, but I rather not have my stomach show through my t-shirt.

*ddkay,* numerous studies have been done that suggest fasting and caloric restriction improve the longevity of a human's life. It has been proven in animals such as rats, and they are now working on proving it for primates. However, due to the primates naturally long lifespan, this area of study has not yet been completed as it is relatively new.

I am a believer of this, and I think it is good to fast/severely restrict calories every so often.

As I have said in a previous post a while back, I jump from 165-185lbs. It takes me about 6 weeks to go from 185 to 165lbs, and then about 6 months to go from 165 back to 185lbs.

Right now, as I am at 181lbs, I am working on going back down to 165lbs so I can start the cycle over again.

As long as you are hydrated and take a multivitamin everyday, I don't believe there are any health effects. If there were, humans would have never made it this far. I can guarantee our great ancestors used to go 40+ hours with 0 calories. You'll be okay if you eat 500 a day. I promise.


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## Cal (Jun 17, 2009)

BMI is a generalized guideline, it is in no way individualized to everybody type.


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## DanFo (Apr 9, 2011)

Too each their own....I'm a skinny fooker. I've tried fatty..high calorie diets and it made no difference even had a doc prescribe steroids ..nothing'... my BMI is below 18 my body fat % is always between 9-11%..My weight is stable wether I eat lots or just normally or wether I'm extra active or inert....I think I've gained 3 lbs since high school (12 years ago) for some of us we just have to deal with what we got. I could use 20 lbs though it would help at least leverage wise


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## hboy43 (May 10, 2009)

Hi:

My take on the BMI is that it is a second order function and people are 3 dimensional. A cubic formula would make more sense but then maybe most people couldn't do the math. According to the formula I am overweight with a BMI of 27, but at 1.93m and 100kg, I am nowhere near overweight in reality.

hboy43


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## nathan79 (Feb 21, 2011)

In my case it's accurate, but only just barely. I am 5'8" and according to BMI my ideal weight range is between 122 and 165 pounds. I'm currently 162 pounds, which puts me at the top end of the normal range. Most people would say I am normal weight or even skinny. I wouldn't want to lose more than 5 lbs.


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## Dmoney (Apr 28, 2011)

I've ranged from probably 180-220 pounds in the past four or five years, and the least healthy I've been is in the 180 pound range. Going to the gym 5-6 days a week and lifting heavy puts a lot of weight on my frame, whereas when I slack off and start eating junk food, I lose all my muscle and it just becomes a big ol' gut. 

Sadly, that's probably where I'm at right now, but I'm getting back on the wagon and doing the gym 4 days a week right now.

All that to say that BMI alone is useless for a lot of athletic builds, but as a general indicator is not useless.


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## MoneyGal (Apr 24, 2009)

Let's talk lifting! What are you doing in the gym?


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## Dmoney (Apr 28, 2011)

Very little now since my condo has only the most basic of equipment. Recovering from a torn ACL/MCL and minuscus as well. 
Doing a lot of running and bodyweight exercises for the moment with a bit of upper body to keep a little definition.


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## MoneyGal (Apr 24, 2009)

I had my ACL, MCL and menicus (two bucket-handle tears) repaired surgically in 2010. I'm not sure whether you are going for surgery but recovery is possible. I'm surprised you would add running but not weight training to your recovery schedule!


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## Dmoney (Apr 28, 2011)

I just don't have the equipment. Gym only goes up to 50lb dumbells which I use for squats and lunges and so on. Leg press machine goes to 170lbs so I use one leg. Bench press machine to 170lbs so one arm for that. 

A lot of improvising, but I actually end up with a pretty good pump after an hour at the gym. 

How do you find it after the surgery? I haven't gone for it yet, and may not bother since it feels really good now. Tore it in January of this year and I'd say it's probably 75% now.


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## MoneyGal (Apr 24, 2009)

Knee feels amazing. I still do a ton of single-leg work - Bulgarian split squats and weighted lunges.


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## donald (Apr 18, 2011)

I think its obsolete,the framework for it was developed what in the 40s?30?People are just plain bigger now!Im 5'10 160 and im spot on just about,but i feel tiny in public(im average in charts to a tee,hieght and weight)Have you ever been around junior high kids now a days?i see 14 yr olds that have barley been growing yet and there all 6'2 with pimples.

This stuff shifts with generations,they used to say 5'9 was average for a man and 5'4 for a women....i think its more like 5'11 for a man and 5'6 for a women.


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## the-royal-mail (Dec 11, 2009)

If you plug in 5' 10" and 160 lbs into the BMI website, I think you'll find that is what they call normal weight.

Yes, people are bigger now. That's the whole point! They should not be bigger. We're eating too much junk food, sitting in front of computers too much, not exercising enough etc. Most of the current obesity epidemic is about fat, not muscle.

It's interesting that most respondents to my poll disagree with the BMI methodology. If you were one of these, what better system would you propose?


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## KaeJS (Sep 28, 2010)

the-royal-mail said:


> If you were one of these, what better system would you propose?


Common sense.


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## Dmoney (Apr 28, 2011)

Body composition...

I think the point was height rather than weight.

The average person is taller than before. Also, unfortunately they're fatter now as well. Much better nutrition is available, hence the height increases (combined with genetic selection among other reasons), unfortunately most don't avail of it and eat cheetos all day.


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## donald (Apr 18, 2011)

I think they should scrap it,i dont understand who society is to deem averages?What is the point?If you got a guy 5'10 160 or a guy 6'3 160 or 180 or 200....what difference does it make?

It depends on people,one of my buddys is 5'11 and weighs about 230 but he carries it in his frame well,according to bmi he is obese(he aint thou)but the chart is suppose to make him feel that way?I dont get the point.


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## andrewf (Mar 1, 2010)

Body fat % is way more informative.


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## the-royal-mail (Dec 11, 2009)

It has to be measurable and thus allow each of us to reach weight loss goals. To say this is a simple question of common sense misses the point. Which is to give specifics about where each of us stands. You can't improve it if you can't measure it.


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## Oxidd1979 (Feb 14, 2011)

Nope, really not accurate for bodybuilders and people who do alot of sports.

My ideal weight if I go with the BMI would be 160lbs. Right now, at 0% body fat I would be at 155 lbs, and a healthy 15% around 175-180.

I'm over that right now, but just lost 30 pounds, and on my way to be under 20%.


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## MoneyGal (Apr 24, 2009)

This is a pretty famous blog post which shows examples of men and women at different bodyfat percentages, and different body compositions (i.e., 15% BF on a muscular woman looks completely different from 15% BF on a "skinny" woman, etc.)

http://www.leighpeele.com/body-fat-pictures-and-percentages


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## Larry6417 (Jan 27, 2010)

The answer partially depends on how BMI is used. It was originally designed to study populations, not individuals. As North Americans have become less fit, our overall BMI has increased. However, there's obviously huge individual variation. Just about every player in the CFL would be considered "overweight" if we tried to use BMI individually. 

See http://www.slate.com/articles/health_and_science/science/2009/07/beyond_bmi.html


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