Forget BMI
Replies
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Ironandwine69 wrote: »BMI tells me I'm fat.
no BMI does not tell you that...
it tells you one of a couple thing
underweight
normal weight
overweight
obese
morbidly obese
if it tells you that you are overweight and you don't think so one of two things is going on.
You are an outlier or you need to reevaluate what you are seeing.
BMI tells me I am obese2 -
gym4life64 wrote: »Ironandwine69 wrote: »BMI tells me I'm fat.
no BMI does not tell you that...
it tells you one of a couple thing
underweight
normal weight
overweight
obese
morbidly obese
if it tells you that you are overweight and you don't think so one of two things is going on.
You are an outlier or you need to reevaluate what you are seeing.
BMI tells me I am obese
Me too.. I am overfat... when I get to my goal weight I'll still be obese, but I don't think I'll be overfat
Edited because I wrote overweight when I meant overfat1 -
stanmann571 wrote: »Packerjohn wrote: »rianneonamission wrote: »Ironandwine69 wrote: »BMI tells me I'm fat.
no BMI does not tell you that...
it tells you one of a couple thing
underweight
normal weight
overweight
obese
morbidly obese
if it tells you that you are overweight and you don't think so one of two things is going on.
You are an outlier or you need to reevaluate what you are seeing.
BMI doesn't take in to account body fat vs muscle mass, so the number is utterly meaningless without understanding body composition.
And what percent of the population is so muscular that the large ranges in the categories of BMI don't resonantly categorize most people.
The correct answer is we really have no idea.
Well according to the CDC only 29% of the US population (self reported) does resistance training 2X a week or more. Since most of the population has sedentary jobs that aren't going to build muscle mass and some of the people doing resistance training are most likely not doing enough to build significant muscle, the % of the population that would be overweight or obese on the BMI scale due to being muscular would be pretty small.
http://www.cbsnews.com/news/cdc-80-percent-of-american-adults-dont-get-recommended-exercise/8 -
I'm one of those people that when I'm down around my ideal weight BMI says that I'm overweight even though my body may be really tight and muscular. I just stopped caring what it said. And I mean, does it really matter? I know when I'm fat and when I'm not. Right now I'm fat.3
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I may, eventually, get close to "normal" BMI range, but I don't believe I will ever be in it. I'm 6'0.5", which means that my maximum weight should be 182.5lbs.
To get myself into "fit" shape, my body fat percentage should be between 14% and 17%, which means my non-fat mass should be between 151.5lbs and 157lbs.
When I had a bodpod scan done back in December, my non-fat mass 183.2lbs, and an overall weight of 233lbs. This means that I would have to lose 50.5lbs, and (of that), 26-32lbs of it would have to be non-fat mass.
Now, add in that I have always led a sedentary lifestyle before I started losing weight. I'm a computer programmer, we're not exactly known for our willingness to get up and move around. So, my non-fat mass isn't likely to change that much.
I might get myself down into the high 190 range, but really, that's as far as I expect it will ever go. Losing more than that will probably put me in a danger zone of too little body fat or too much non-fat mass having been removed.
Physically, I've always been completely ordinary. Nothing special about me. And yet, here I am stating that I am unlikely to *ever* have a "normal" or "healthy" BMI, even if I get myself down to 10% body fat (which is a level that many athletes have a hard time getting to).
BMI is broken. You might be one of the lucky ones for whom it works, but BMI is fundamentally broken for measuring an individual. Don't use it, don't rely on it. Get actual body fat scans done, or just settle for looking in a mirror honestly, and deciding if what you see is fat or not.
But don't push BMI. It's not a good tool.1 -
rianneonamission wrote: »Ironandwine69 wrote: »BMI tells me I'm fat.
no BMI does not tell you that...
it tells you one of a couple thing
underweight
normal weight
overweight
obese
morbidly obese
if it tells you that you are overweight and you don't think so one of two things is going on.
You are an outlier or you need to reevaluate what you are seeing.
BMI doesn't take in to account body fat vs muscle mass, so the number is utterly meaningless without understanding body composition.
not so much...you have to understand the history of BMI and what is was used for and why it is still used before you can make blanket statements like that..rianneonamission wrote: »It may categorise most, but it doesn't categorise everyone. So to say to a stranger that, because BMI tells them they are overweight when they are not, they are lying to themselves or have a skewed self image is ridiculous.
and I didn't just say skewed self image I believe I said "outlier" first.
and I would like to see the BF% of those who are claiming outlier status...
I am not disputing that there are outliers there sure are but I also know that BMI is a good measurement for most...and when coupled with weight and other indicators such as BP etc it gives a good read on health and weight....and yes of course there are limitations.
PS I used to argue that BMI wasn't a good measure due to personal bias...8 -
macchiatto wrote: »That is interesting; thanks for posting. My husband is one for whom BMI is off. He's been losing weight and does still have a bit more to lose but nothing like BMI would indicate. I also just looked at the measurements we last took for him (he's lost a bit more since then) and waist was 39.75" even though he's now right on the border between "obese" and "overweight" per BMI.
I don't have time to research this more right now, but anyone know for this if waist measurement they're going by is the narrowest point between rib cage and hips, or belly button level? My belly button definitely migrated lower thanks to pregnancy so now that measurement is pretty close to my hip measurement.
BMI is 20.1 now, true waist is 28.5" but belly button level "waist" measurement is right around 35".
For women it's the narrowest point.1 -
Oh, jeez, I just realized that I was calculating my *maximum* weight according to BMI. That 182.5lbs is a BMI of 25 for me. If I go for the low end, a BMI of 19? My weight should be 138.7lbs. That's laughably implausible for me.1
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I've always gone by the old fashioned pinch an inch.0
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Recall that the BMI formula is just: (Weight in kilograms)/(Height in meters)^2
Given the incredible simplicity of the metric, I'm always wondering: what do people expect? Of course people who are muscular will appear to have a high BMI. Even when you BMI is 25 or greater, the statistics don't say much about your health.
Here is a good blurb on BMI:
https://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/
If you really want to see how BMI compares with DXA (which is the gold standard for measuring percentage body fat) you can look at this paper:
https://www.ncbi.nlm.nih.gov/pubmed/16044176
The conclusion of the above paper is that BMI predictions of body fat percentage correlate well with DXA, but looking at the data, I see that the DXA measurement could be different from the BMI prediction by as much as +/-10%. In other words, your BMI might predict a body fat of 20%, but yours is really 10% or 30%, which is highly significant. (See below for data from Steinberger 2005).
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trigden1991 wrote: »Just look in the mirror and take an honest look at yourself.
Yup...KISS2 -
Not sure how you kitten something, but okay lol.0 -
pedermj2002 wrote: »Oh, jeez, I just realized that I was calculating my *maximum* weight according to BMI. That 182.5lbs is a BMI of 25 for me. If I go for the low end, a BMI of 19? My weight should be 138.7lbs. That's laughably implausible for me.
Yeah... it's a range for a reason. Not everyone should be at the bottom of the range just as not everyone should be at the top of the range.
Normal BMI range =/= healthy
It's very easy to be overfat in the normal BMI range, which is opposite of what many people want to believe (i.e. that it's easy/common to have a good body fat % in the overweight/obese ranges).
BMI is a single tool in a plethora of measurements to determine if someone is at a healthy weight.4 -
Bottom line is BVI will reduce the percentage of outliers
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VintageFeline wrote: »macchiatto wrote: »That is interesting; thanks for posting. My husband is one for whom BMI is off. He's been losing weight and does still have a bit more to lose but nothing like BMI would indicate. I also just looked at the measurements we last took for him (he's lost a bit more since then) and waist was 39.75" even though he's now right on the border between "obese" and "overweight" per BMI.
I don't have time to research this more right now, but anyone know for this if waist measurement they're going by is the narrowest point between rib cage and hips, or belly button level? My belly button definitely migrated lower thanks to pregnancy so now that measurement is pretty close to my hip measurement. BMI is 20.1 now, true waist is 28.5" but belly button level "waist" measurement is right around 35".
For women it's the narrowest point.
Perfect; thanks!0 -
BMI is a reasonable guide for more people than those for whom it isn't, in the sense that most people can find a weight that would be healthy for them somewhere in the normal BMI range. But it's a screening tool, not a definitive answer for any one individual.
When BMI said I was obese (at BMI 30.4), I was, even though all my friends said "you're not fat!" when I mentioned that I was. I knew then, and now demonstrate (at a BMI around 21) that I have essentially no hips, bone-wise.
Y'know what it does when BMI is deprecated by the small percentage of people who are much more muscular than average, or who have unusual body types? It gives people at an unhealthily high weight, people to whom their BMI should be a wake-up call, another reason to lie to themselves and feel justified, 'cause Science.
A guy I know said he was talking about his weight loss plans to a 3rd party, and mentioned his obese BMI. She said incredulously "You're not obese! Why, if you're obese, then I would surely be obese, too." He didn't tell her she was . . . but she was.18 -
BMI is a single tool in a plethora of measurments to determine if someone is at a healthy weight.
And that nicely ignores the entire point of the previous post I made: BMI may actually work for some people. You might be one of the lucky ones it *does* work for. But a tool to help diagnose health with a failure rate of 18% is not a useful tool. That's nearly one in five.
Think of it this way: I set out 5 cups in front of 5 people. Four of them have sugar, one of them has salt. You get to pick one, and whatever you pick you have to consume all of it. Only four of you have to pick a cup though. Would that last person take the last cup, or simply pass?
Change it to cups of water, one of which is poisoned. Make it just you. Would you take your chances on it then?
I doubt I'd be willing to take a cup in either of those challenges. Most other people wouldn't either. And yet, using that tool, people are labeled, categorized, and viewed as either healthy or unhealthy. It's really bad, and needs to stop being used.
Oh, and here's another tidbit that came from that article: "31 percent who were of normal weight according to B.M.I. had excess body fat." That means that, for 49% of the people out there, BMI gives them broken information about their current fat levels.
This means that for a mere 51% of the population, BMI is useful.
When you know that, BMI is not a reasonable guide anymore.
*edit* I screwed up math.31+18 is 49, not 59. Woops.0 -
BMI is a reasonable guide for more people than those for whom it isn't, in the sense that most people can find a weight that would be healthy for them somewhere in the normal BMI range. But it's a screening tool, not a definitive answer for any one individual.
When BMI said I was obese (at BMI 30.4), I was, even though all my friends said "you're not fat!" when I mentioned that I was. I knew then, and now demonstrate (at a BMI around 21) that I have essentially no hips, bone-wise.
Y'know what it does when BMI is deprecated by the small percentage of people who are much more muscular than average, or who have unusual body types? It gives people at an unhealthily high weight, people to whom their BMI should be a wake-up call, another reason to lie to themselves and feel justified, 'cause Science.
A guy I know said he was talking about his weight loss plans to a 3rd party, and mentioned his obese BMI. She said incredulously "You're not obese! Why, if you're obese, then I would surely be obese, too." He didn't tell her she was . . . but she was.
I agree with this. It is appropriate for most people...I believe a substantial majority.
There are MANY muscular people who are also fat. Just because you lift heavy a few times a week doesn't mean you aren't still overweight or obese. A lot of people like to lie to themselves and say BMI doesn't apply to them because they lift.
I can tell when a person would be overweight or obese based on BMI yet have a healthy body fat level. They LOOK like they lift a lot of weight. I think of NFL linebackers like James Harrison. I'm sure BMI does say he is obese, but anybody who looks at him can tell there is no spare fat. Yet, I see people post pics here all the time and claim BMI doesn't work in their case. In A FEW of those cases, I would agree and think they are correct. But for most, I may see some muscle, but I also see a nice layer of fat covering most of it. Whether they want to believe it or not, these people are probably overweight.9 -
pedermj2002 wrote: »BMI is a single tool in a plethora of measurements to determine if someone is at a healthy weight.
And that nicely ignores the entire point of the previous post I made: BMI may actually work for some people. You might be one of the lucky ones it *does* work for. But a tool to help diagnose health with a failure rate of 18% is not a useful tool. That's nearly one in five.
Think of it this way: I set out 5 cups in front of 5 people. Four of them have sugar, one of them has salt. You get to pick one, and whatever you pick you have to consume all of it. Only four of you have to pick a cup though. Would that last person take the last cup, or simply pass?
Change it to cups of water, one of which is poisoned. Make it just you. Would you take your chances on it then?
I doubt I'd be willing to take a cup in either of those challenges. Most other people wouldn't either. And yet, using that tool, people are labeled, categorized, and viewed as either healthy or unhealthy. It's really bad, and needs to stop being used.
Oh, and here's another tidbit that came from that article: "31 percent who were of normal weight according to B.M.I. had excess body fat." That means that, for 59% of the people out there, BMI gives them broken information about their current fat levels.
This means that for a mere 41% of the population, BMI is useful.
When you know that, BMI is now an unreasonable guide for more people than those for whom it isn't.
I didn't ignore your point at all. You made a point about the low end of the normal BMI range being implausible for you, and I agreed. For many, being at the low end of the normal BMI range is not appropriate. Neither is being at the high end of the BMI appropriate for many. BMI is a range to account for factors like sex and body type. It's a single measure of many for determining a healthy weight range, but too many people, especially on MFP where we have an overly biased population, want to believe that they are BMI outliers.
Being a BMI outlier is mostly to do with muscle mass. High muscle mass = overweight/obese BMI but low bodyfat %. Low muscle mass = normal BMI but high bodyfat %. For people who need to lose weight, BMI is useful tool for determining how much weight they should lose to lower their weight-related health risks. Like @AnnPT77 I've seen one too many people who really do need to lose fat, disregard BMI because they've heard people disparage it as a measure of healthy weight.0 -
I think you didn't read the link I provided, so I'll spell it out here: https://www.nytimes.com/interactive/projects/cp/summer-of-science-2015/latest/how-often-is-bmi-misleading
BMI is a misleading statistic, and badly so. Under the absolute best possible interpretation of that article (being most favorable to BMI), nearly one out of every 5 people will be misled about their current fat levels and how healthy those fat levels are for them. Under the worst possible interpretation of that article, it becomes one out of every two.
To put it in human terms: If you work with a team of four other people, then one of the people on your team (including you) is being misled by BMI (under the best possible conditions). Under the worst, at least two people on that team are.
And the BMI data can be wrong in *both* directions: It can tell you you're okay, even though you're in dangerously high body fat percentage territory. It can tell you you're not okay, even though your body fat is extremely low and muscle mass is extremely high.
Your interpretation of what an "outlier" is, with respect to BMI, is flawed. When you state that being an outlier is mostly to do with muscle mass, you're thinking of people who have lots of muscle mass for whatever reason. The other direction happens too, where they have too much body fat and not enough muscle mass, and those people are actually in danger but will be told they're okay because their BMI labels them as "normal".
That's why I advocate for getting BF % measured using *anything* other than BMI. Find out the reality about your body and work with that. You can even go with pictures online for a free way to compare (see https://www.tasteaholics.com/wp-content/uploads/2015/10/Body-Fat-Percentage.jpg for one example). Literally *any* option is better than BMI, but people get hung up on it because it's all they know.1
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