Is BMI really a joke?

schnarfo

I have been on MFP for some time and have come across a lot of posts about how BMI is generally inaccurate and not worth paying attention to. Is this just a way for overweight people to feel better about themselves or is there actually some merit to this?

I currently have a BMI of 17.2 but a healthy BMI is 18.5 - I have been trying for a while now to get back to that so called healthy BMI but is there any point if it shouldnt be accepted?

fteale

I think BMI is pretty accurate as a measure of healthy weight. Those who say it isn't are generally people with a distorted image of what humans are supposed to look like. A healthy BMI covers a wide range, it's not as if you get one ideal weight. I can be between 112 and 150lbs and be a healthy weight. I certainly wouldn't want to be out either end of that range!

It is more dangerous to be underweight than slightly overweight, so I think aiming to get up to healthy is a good plan.

ItsLessOfMe

My BMI is obese and will be until I loose 5 more lbs. That doesnt make me feel better about myself at all. So I'm not sure what you are saying.

If you've done all you can to gain weight I would say relax. I can't stand the BMI. I'm not where I want to be weight wise but I dont consider myself obese...

schnarfo

My BMI is obese and will be until I loose 5 more lbs. That doesnt make me feel better about myself at all. So I'm not sure what you are saying.

If you've done all you can to gain weight I would say relax. I can't stand the BMI. I'm not where I want to be weight wise but I dont consider myself obese...

Sorry I meant is not believing in BMI a tool for people to feel better about themselves not that BMI puts you into a certain category.

Athena413

I think BMI can be a decent guideline, but nothing more than that. The only things it takes into consideration are your height, your weight, and your age. Thus, you can have a very muscular person will low body fat that is in perfect shape with a distorted BMI because muscle is more dense than fat. It also doesn't take into consideration bone density or any sort of water weight...which continuously fluctuates.

rurukidoo

I think it's more because the BMI scale can't take muscle or fat % into account. So you could have a body builder who has for example 7% body fat, but the BMI scale would say that he is obese. Hope that makes sense....maybe someone who knows better than I will come and explain it better.

ShrinkingNinja

BMI is merely a guideline. I do not find it to be truly accurate at all. The BMI charts list Lance Armstrong as being overweight. Can anyone truly say that he is overweight?

LauraJo08

When talking to my doctor, he said that BMI can be considerably off for a couple different reasons:

1) you are an athlete with high muscle mass.
2) you have a broader or slimmer build.

BMI charts are based on average body builds (bone structure and such). So if you quite broad in the shoulders and hips or quite narrow, the BMI chart may not apply to you as well.

In general though, I would talk to your doctor before you make lifestyle changes based on a supposed chart.

mariapuhl

The reason a lot of people don't like BMI is because it ONLY takes into account height and weight.

For example, take two men, both 5' 10", and both with a BMI of 32 - so around 220 pounds.

That is in the "obesity" range of BMI. One though, could have a 22% body fat, while the other has 45% body fat. Which one do you think is healthier?

Or, using myself as an example. Right now, I am at a BMI of 25. But my body fat is still at 38%. I don't really need to lose more weight, but gain muscle. The BMI part doesn't tell me that at all.

ShrinkingNinja

I have been on MFP for some time and have come across a lot of posts about how BMI is generally inaccurate and not worth paying attention to. Is this just a way for overweight people to feel better about themselves

Surely you didn't mean this the way it reads....

TourThePast

BMI is a useful and simple way of suggesting a range of weights that might be considered healthy / overweight / obese for people of a particular height.

People are very fond of pointing out that a bodybuilder with a huge muscle mass and very low body fat %, comes out as obese. Far as I'm concerned that's a straw man argument. Very few people can get to build that much muscle, and cut that much fat off their bodies without learning FAR more than they'd need to know, to understand that BMI doens't apply to them.

What it cannot accurately do is give one weight that one person of one height should be. What it's great at doing is showing clearly that the typical "person X" who is seeking initial information, is severely over or under weight.

Remember, BMI is based on HEALTHY weights, not what you or anyone else might think looks good. At 90lb, I'm a healthy weight, but to my eyes, I look awful!

jonikeffer

I'm sure some people are using that as an excuse. However if you know that your body type is truly not typical....if you are very muscular/amazonian for a woman, for example...the BMI guide *can be* misleading. But most people will be healthy within that range. If you are close to that but under, and feel well and fit where you are, I wouldn't try to force yourself into the box. I know at 5'0" and being very petite, I could fall off the bottom of my range and still be perfectly healthy. Even at 95 lbs I have never looked "skinny". (Of course I am far from 95 lbs now and am not shooting for that as my goal at age 35.)

AlistairBrown

So, let me get this right, you are saying that it doesn't matter what shape you are natually, the BMI scale in your opionion is a valid scale. That is a joke! I am 5' 10", and currently 14 stone and 10 pounds, thats about 93 kilos, having lost three stone (18 kilos) yet according to BMI I am still obese!! I have played sport all my life, and am generally considered fit, I don't smoke or drink. You are saying that someone, with a much quicker metobolic rate, who smokes and drinks and is a small frame, but has what you would consider a much heathier BMI is healthier than me?

schnarfo

OK I get the whole muscle thing and making athletes appear to be overweight when they clearly arent but what about the opposite end and being under the healthy BMI.

Are to still ignore it then or is it something I really need to be aiming for? I work out 6 days a week and do heavy weights 3x a week. My profile pic was taken 3 weeks ago so you can see I am not super skinny and that I look healthy so do I need to be adding these extra 7lbs to be within a healthy BMI or can I just stay as I am and still be healthy? I dont mind trying to gain the weight if thats what is needed for me to be healthy but I dont wish to do it if its not necessary because BMI is generally inaccurate and should be ignored.

Mindful_Trent

The problem with BMI is it doesn't take into account your body fat %. You can have two people, same height, same weight, same BMI, but one person is 35% body fat and the other person is 10% body fat - you'd better believe that the 1st person has a lot of work left to do, while the latter is very healthy. Someone posted a picture on another thread of this body-builder who is clearly in top physicial condition but is considered "obese" by BMI standards - clearly illustrating its flaws.

For the average person it can be a slightly useful tool but in general, you're much better off getting your body fat tested (using a reliable method) on a periodic basis and using that as a measure of your progress.

Edited to add - since some people have a problem with the body-builder example, another example is a woman who is technically a healthy weight, healthy BMI, but who has a high body fat percentage - the "skinny-fat" person. Technically a healthy weight, but really not all that healthy.

If you're including weight lifting and doing well-rounded exercise in addition to healthy diet to lose weight, you're probably fine going off BMI as a general indicator. It's the people at the far ends of the spectrum - bodybuilders and people who don't work on retaining muscle at all for whom BMI is a very poor measurement of health.

fteale

I would suggest you get your BF % measured, and if it is under 17%, put on those 7lbs.

Huffdogg

BMI is quite simply a joke. Any metric that alleges to give a useful portrait of your health situation with only these two pieces of information is completely useless. A formula that compares height and weight and can supposedly tell whether or not you are healthy? Give me a break. It doesn't take into account bone structure, muscle mass, or any other variable beyond those two pieces of information. According to BMI, my ideal weight is in a range that would have me waste away to look like a death camp refugee to achieve. Don't pay any attention to it EVER.

Athena413

If you're only 7 lbs away from "healthy" I wouldn't worry too much about it. You're obviously not malnourished and you don't look like a bean pole. Your organs aren't shutting down, so I don't think you're too far underweight.

RMinVA

It's a guidline. And already lots of people have said it doesn't take into account build, muscle mass etc. I used to say that too - "I'm big boned..." And seriously, how many people are built like Lance Armstrong? Maybe other professional athletes...and I would agree that it is a useless measurement for them. But for us mere mortals....

For now, I am still technically "obese," and both of my parents are type 2 diabetics. My doctor would like me to be in the "healthy" range due to family history. I have absolutely no health issues and have a healthy lifestyle, so he doesn't give me a hard time about it. But from my doctor's perspective and experience: people that were beyond the "healthy" ranges tended to have more health problems overall, PERIOD!! I WANT to lose more, and my ultimate target weight, for various reasons is well within that range.

And of course, there are exceptions to every rule...

kmeekhof

For the "average" or "typical" person it is fairly accurate... for someone who has a very low body fat percentage due to being super fit and a lot of muscle mass it is not as accurate. The same could be said for somebody who is naturally thin/low body fat percentage, but does not eat healthy or workout... they will have a low BMI, but does not mean they are healthy.

scheys76

BMI doesn't take into account muscle mass and bone structure. My scale does fat percentage for me. at 0% body fat I would weight 152 lbs. The "normal" range for me according to the BMI charts on the Center for Disease control website is 119 - 157 lbs. So accourding to that chart, at 3.2% body fat I would just barely be in the normal range...

And that's provided I don't gain any more muscle...