Forget BMI

SezxyStef · May 2017

pedermj2002 wrote: »

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.

to the bolded part...bf% depending on how it is measured is no better...even Dxa scans are misleading depending on hydration levels between the two test etc...with variances showing up in lab settings.

BMI is not a measure of BF% anyway it is a measure of weight...and for that it is valid for the majority of people.

and to be quite frank on the other statement I highlighted...that is so wrong on so many levels.

For example...a friend gained 10lbs in 2 days based on scale weight...piss poor option but people use it all the time.

Body fat % measure by BIA scales are so wrong in so many ways....calipers ditto

tape measures are off often as well cause can you remember exactly where you measured and are you swollen from water retention etc.

no one number can give you an accurate reading of your health or weight or BF%...we as individuals need to take them all and then add them all up and look in the mirror and then we have our answer...are we healthy? are we where we want to be?

AnnPT77 · May 2017

pedermj2002 wrote: »

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.

And I don't think you read the link that @Jthanmyfitnesspal provided:

https://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/

You make it sound like we're automatically sending people who fall outside the normal BMI range off for execution or something (or, bizarrely, off to eat a cup of salt, for some reason). Or at least that they should blindly act on their BMI "prescription".

But no. We're looking at them more closely to see if there's really a weight problem, because BMI is an easy, inexpensive screening tool, not a prescription. Per the link above, "BMI can be used as a screening tool for body fatness but is not diagnostic."

Also, they add: " . . . a relatively high BMI can be the results of either high body fat or high lean body mass (muscle and bone). A trained healthcare provider should perform appropriate health assessments in order to evaluate an individual's health status and risks."

Which is really not very much like eating a cup of salt. Or sugar (yuck), for that matter.

Plus, it's from the actual CDC, the exact kind of evil pushers who promulgate the wicked, wicked BMI system, so I'd consider them pretty authoritative about how to use it.

Ruatine · May 2017

pedermj2002 wrote: »

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.

Except that I specifically stated that it goes both ways.

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 %.

Also, yes, I did look at your article, but I honestly found some of the data they were linking suspect, as it wasn't what the studies were saying (typical of media).

Both of these studies, on the other hand, are quite interesting and aren't filtered through a journalist's non-scientific, headline grabbing bias:

http://ajcn.nutrition.org/content/89/2/500.full (Comparisons of percentage body fat, body mass index, waist circumference, and waist-stature ratio in adults)
http://ajcn.nutrition.org/content/72/3/694.full (Healthy percentage body fat ranges: an approach for developing guidelines based on body mass index)

BMI is not perfect. BMI is not an indicator of a specific body fat % (I say this, because you said, "That's why I advocate for getting BF % measured using *anything* other than BMI."), although in one of the studies I linked, the researchers gave it a damn good go.

VintageFeline · May 2017

And whilst it can be a higher occurence in males to fall outwith the BMI range and still be a healthy BF% It would be a lot more unusual for women.

I am currently somewhere around 27% at a guess body fat wise. 165lbs. That's 14lbs above upper end of BMI, a bit of a calculation would have me around 22% at about 145lbs though I'm potentially shooting for a bit lower, I'll see. So though it appears I have a good amount of muscle thanks to an athletic past, I am still perfectly able to get into a healthy BMI by some way. And if I put on 5lbs of lean mass once in maintenance I'd STILL be in the healthy BMI range.

So for the vast majority of the population it's just fine to use it as a guideline. Which is all it was ever intended to be.

pedermj2002 · May 2017

SezxyStef wrote: »

BMI is not a measure of BF% anyway it is a measure of weight...and for that it is valid for the majority of people.

This is completely incorrect. BMI is a measure of weight compared with height. The formula is actually pretty simple: weight (in kg) divided by the square of the height (in meters). That's it. BMI is not a measure of weight, it's a measure of a proportion of weight to height.

Do other methods have issues? Sure, all the time. None of them are as badly misleading as BMI though, not with how BMI is used.

Look, for me, today, my numbers are 1.84m and 98.07kg. So, plugging them in: 98.07/(1.84*1.84) = 28.97 BMI. Maximum "normal" BMI is 25, so I've got a ways to go before I reach "normal" BMI. Going by this picture, I'm somewhere in the 20%-24% range. Going by the New York Times article, I'm in a "healthy" range of BF% (I want to be lower than that, so I'm working on it, but that's where I am now).

But anything is better than BMI. A tool with an error rate that high is a tool that needs to be relegated to the dustbin of history. Calipers can be miscalibrated. DXA scans can be impacted. BodPods have their own errors. Tape measures might not be measuring the exact same locations on the body from day to day. Even plain old scales can be wrong depending on their exact location on the earth, if they haven't been calibrated for that location or are sitting on material that affects their ability function (carpet vs tile, for instance). But what all of them have in common is accuracy, even on a bad day, that beats out BMI.

Yes, the CDC pushes BMI. Yes, it can be used as a tool for a significant chunk of the population. But an error rate that high (and especially on false positives where the person is told they're okay!) is absolutely horrific.

That's why I used the sugar/salt and poison/not poison analogies. Errors are places where a tool breaks down. By definition, you can't predict them (if you could, you'd prevent them), making them effectively random. So, would you be willing to trust a random "grab this cup and drink it" if you knew that 31% of the time it would give you a problem? I know that I wouldn't, and I'd be shocked if others would, *especially* if the benefit from it is so minimal.

That's why I say to abandon it. It's not complex math. And it provides false information all too often.

Packerjohn · May 2017

pedermj2002 wrote: »

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.

I think your BodPod measurement is inaccurate. Can't see someone 233 lbs at 6 ft tall being around 20% bodyfat if they have never been active. IMO, does't pass the smell test. I'd think more like the 25-30+% range based on self described lifestyle.

SezxyStef · May 2017

pedermj2002 wrote: »

SezxyStef wrote: »

BMI is not a measure of BF% anyway it is a measure of weight...and for that it is valid for the majority of people.

This is completely incorrect. BMI is a measure of weight compared with height. The formula is actually pretty simple: weight (in kg) divided by the square of the height (in meters). That's it. BMI is not a measure of weight, it's a measure of a proportion of weight to height.

Do other methods have issues? Sure, all the time. None of them are as badly misleading as BMI though, not with how BMI is used.

Look, for me, today, my numbers are 1.84m and 98.07kg. So, plugging them in: 98.07/(1.84*1.84) = 28.97 BMI. Maximum "normal" BMI is 25, so I've got a ways to go before I reach "normal" BMI. Going by this picture, I'm somewhere in the 20%-24% range. Going by the New York Times article, I'm in a "healthy" range of BF% (I want to be lower than that, so I'm working on it, but that's where I am now).

But anything is better than BMI. A tool with an error rate that high is a tool that needs to be relegated to the dustbin of history. Calipers can be miscalibrated. DXA scans can be impacted. BodPods have their own errors. Tape measures might not be measuring the exact same locations on the body from day to day. Even plain old scales can be wrong depending on their exact location on the earth, if they haven't been calibrated for that location or are sitting on material that affects their ability function (carpet vs tile, for instance). But what all of them have in common is accuracy, even on a bad day, that beats out BMI.

Yes, the CDC pushes BMI. Yes, it can be used as a tool for a significant chunk of the population. But an error rate that high (and especially on false positives where the person is told they're okay!) is absolutely horrific.

That's why I used the sugar/salt and poison/not poison analogies. Errors are places where a tool breaks down. By definition, you can't predict them (if you could, you'd prevent them), making them effectively random. So, would you be willing to trust a random "grab this cup and drink it" if you knew that 31% of the time it would give you a problem? I know that I wouldn't, and I'd be shocked if others would, *especially* if the benefit from it is so minimal.

That's why I say to abandon it. It's not complex math. And it provides false information all too often.

it is not completely incorrect actually....and I actually know the history and how it is calculated and what it is used for so I don't need a lesson thx.

But you are fighting a losing battle...BMI is a good for what it is used for...just like other tests that aren't 100%...

And if you for one minute think a scale or a set of calipers or a BIA scale is 1oo% better than BMI and you ahve said it more than once I am out as you can lead to water but you can't force to drink and being ignorant is your choice.

pedermj2002 · May 2017

I had begun weight loss by then, and was down by 40lbs. Maybe the biking I started a few months before made enough of a difference? I don't know. I just know what I had on the printout they gave to me.

AnnPT77 · May 2017

pedermj2002 wrote: »

I had begun weight loss by then, and was down by 40lbs. Maybe the biking I started a few months before made enough of a difference? I don't know. I just know what I had on the printout they gave to me.

I can absolutely believe that BMI doesn't work for you, in exactly the way you describe.

However, if it does work for 80% of cases, (or 60% or some other majority percentage - not quibbling), you're pretty much the definition of an outlier.

I don't see why that means we ought to throw it out as an inexpensive screener, a rough approximation.

MFP's calorie calculator is howlingly incorrect for me - on the order of 30% off (as are other similar calculators I've tried, though some are slightly closer). That doesn't motivate me to tell everyone to ignore the calculators . . . though it does make me want to help others understand how the calculators work, what they're good for, and that they aren't straight-up spot-on gospel for everyone. However, they give pretty decent estimates for most people, useful as a starting point.

I don't see why BMI is any different: It's an approximation, it's a screener, it's cheap, it gives an estimate that can be used as a starting point. People who think it's wonky for them should talk to their doctor, seek out a more precise diagnostic, etc.

bbell1985 · May 2017

I'm pushing right outside of a normal BMI right now. I know I'm not super slim but I'm pretty fit. I'm not concerned about what it says because I'm athletic, but I am a few pounds above the physique I prefer.

Packerjohn · May 2017

pedermj2002 wrote: »

I had begun weight loss by then, and was down by 40lbs. Maybe the biking I started a few months before made enough of a difference? I don't know. I just know what I had on the printout they gave to me.

Understand you are going off the test result. A few months of casual biking does not build much muscle. As you lose weight, I would not be surprised if you found the 180 range just fine.

GottaBurnEmAll · May 2017

Something occurs to me in this discussion which is a point that hasn't been raised, and please correct me if I'm wrong, but when you're given a figure in those scans for fat free mass, that includes everything including water in your tissues, and that weight also decreases when you lose fat as you lose additional weight. As you lose weight you will also lose additional muscle tissue.

In other words, I'm kind of perplexed from how I understand weight loss works how this discussion is continuing on the premise that a reading on fat free mass is being considered to be a constant that will stay no matter what happens with weight loss.

I didn't think that was how it worked.

I read back and I see where I'm misunderstanding this somewhat, but I'm not sure this shouldn't have been said because of it sounding like an impossibility that fat free mass would "be removed".

I think the bod pod was wrong, frankly.

gmallan · May 2017

Ironandwine69 wrote: »

BMI tells me I'm fat.

Well that's actually the main problem with BMI. It doesn't tell you anything about how much fat you have just scale weight compared to height.

SezxyStef · May 2017

GottaBurnEmAll wrote: »

Something occurs to me in this discussion which is a point that hasn't been raised, and please correct me if I'm wrong, but when you're given a figure in those scans for fat free mass, that includes everything including water in your tissues, and that weight also decreases when you lose fat as you lose additional weight. As you lose weight you will also lose additional muscle tissue.

In other words, I'm kind of perplexed from how I understand weight loss works how this discussion is continuing on the premise that a reading on fat free mass is being considered to be a constant that will stay no matter what happens with weight loss.

I didn't think that was how it worked.

I read back and I see where I'm misunderstanding this somewhat, but I'm not sure this shouldn't have been said because of it sounding like an impossibility that fat free mass would "be removed".

I think the bod pod was wrong, frankly.

exactly ...my son is 6 ft 4...190lbs...recently gained 10....and at 180 he was still not too lean...and he wears a size 11 shoe...aka not a small lad @22 years old...

my husband is 184lbs....at 5 ft 11...not lean but not fat either...a good weight...solid...but has a bit of a belly...

WakkoW · May 2017

MoiAussi93 wrote: »

AnnPT77 wrote: »

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.

So much this. So many think that just because there is a layer of muscle under the fat that they are an outlier. What that really means is they will likely be okay at a higher BMI. Those with no muscle should shoot for the lower end. The BMI range is huge.

There are outliers, but not everyone who lifts is one. Most aren't.

I agree with the poster upthread who said that one is more likely to be overfat than underfat in the healthy range.

I used to believe I was an outlier. Turns out I was overfat. I am happy at the higher end of the range.

Machka9 · May 2017

MoiAussi93 wrote: »

AnnPT77 wrote: »

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.

This ^^

SezxyStef · May 2017

MoiAussi93 wrote: »

AnnPT77 wrote: »

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.

I said this on page one in a sentence and was basically told I was being mean for telling strangers that they are lying to themselves or have a skewed self image.

moonstroller · May 2017

rianneonamission wrote: »

SezxyStef 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.

You are exactly on target. When I was in excellent shape years ago I was doing a lot of lifting so I weighted 178 pounds with under 7% body fat and wore size 30 pants. BMI had me as being overweight, but it's overall body composition that matters.

WakkoW · May 2017

SezxyStef wrote: »

MoiAussi93 wrote: »

AnnPT77 wrote: »

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.

I said this on page one in a sentence and was basically told I was being mean for telling strangers that they are lying to themselves or have a skewed self image.

You did. You wrote "You are an outlier or you need to reevaluate what you are seeing".

I assumed the "you" was a general "you" and not directed towards anyone specifically. Honestly, no idea why the issue with the statement.

not_a_runner · May 2017

WakkoW wrote: »

MoiAussi93 wrote: »

AnnPT77 wrote: »

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.

So much this. So many think that just because there is a layer of muscle under the fat that they are an outlier. What that really means is they will likely be okay at a higher BMI. Those with no muscle should shoot for the lower end. The BMI range is huge.

There are outliers, but not everyone who lifts is one. Most aren't.

I agree with the poster upthread who said that one is more likely to be overfat than underfat in the healthy range.

I used to believe I was an outlier. Turns out I was overfat. I am happy at the higher end of the range.

Agree with this and the previous quote.
There are certainly some people that BMI may not work for, but I think for the large majority (especially women) it's pretty accurate.
I lift and have been told I must have oodles of muscle. But I'm also well over 40% bf. If I were at a reasonable bf % I would easily fall into the "healthy" weight range. And as I get closer I've realized I don't have nearly as much muscle as I once thought.
Even many high level female figure/physique competitors fall into the "Healthy" BMI range. (Dana Lynn Bailey is something like 5'4'' and 130 lbs, well within the healthy weight range even thought she looks huge.)

If you like having a little extra body fat and don't want to lose the extra 10 lbs to put you within the healthy BMI range than you can do you, just don't complain that BMI is "zomg so inaccurate" for you because you want to weigh x and it says you should be y-z.

Forget BMI

Replies

Categories