Why You Should NEVER Use BMI

chivalryder

"While the formula previously called the Quetelet Index for BMI dates to the 19th century, the new term "body mass index" for the ratio and its popularity date to a paper published in the July edition of 1972 in the Journal of Chronic Diseases by Ancel Keys. BMI was explicitly cited by Keys as being appropriate for population studies, and inappropriate for individual diagnosis. Nevertheless, due to its simplicity, it came to be widely used for individual diagnosis, despite its inappropriateness."

There you have it.....not appropriate for individual diagnosis.
That's my story and I'm sticking to it.

I will second this!

Seriously, everyone on here who said "it is ok if you are an average person" was basically saying it was ok for me. If it were ok for me, then I should be able to get my BMI a lot lower than just under overweight and still be healthy, but I cannot. According to the BMI, I will always be considered overweight, and thus at health risk.

It's a crock of *kitten*.

DonniesGirl69

"While the formula previously called the Quetelet Index for BMI dates to the 19th century, the new term "body mass index" for the ratio and its popularity date to a paper published in the July edition of 1972 in the Journal of Chronic Diseases by Ancel Keys. BMI was explicitly cited by Keys as being appropriate for population studies, and inappropriate for individual diagnosis. Nevertheless, due to its simplicity, it came to be widely used for individual diagnosis, despite its inappropriateness."

There you have it.....not appropriate for individual diagnosis.
That's my story and I'm sticking to it.

I will second this!

Seriously, everyone on here who said "it is ok if you are an average person" was basically saying it was ok for me. If it were ok for me, then I should be able to get my BMI a lot lower than just under overweight and still be healthy, but I cannot. According to the BMI, I will always be considered overweight, and thus at health risk.

It's a crock of *kitten*.

Yes.....absolutely a crock of *kitten*. In my humble opinion.

myofibril

BMI is a good guide and in general you can calculate the percentage body fat based on the BMI, but there would be differences for each person.

Yeah, pretty much.

Unless you are pretty athletic it is a reasonably valid measure of body fat percentage:

http://www.ncbi.nlm.nih.gov/pubmed/2043597

LOL

The calculation on there said that I have a BF% of 20%! HAH! That's off by nearly 15%! I have a BF% of 35!

How did you obtain your BF% as 35 out of curiosity? From the stats you gave in OP you should have a BMI of about 30 which equates with a rough BF% of about 26-27.

I'm not saying that this is right or that calculation holds true for you but it does seem a little unusual.

chivalryder

OK, how about this:

Why would someone need to use the BMI to decide whether or not they need to lose weight? If you're asking yourself that question, chances are, you know the answer. You should NOT use the BMI to decide how much weight to lose! If I did, I would be aiming for the middle of the scale. That would put me below my current lean mass. It would be impossible to attain, and I would get really sick by trying.

So why use it at all?

If you want more solid answers on exactly what you goal weight should be, you should be speaking to a professional who actually know how to measure and assess your situation properly.

chivalryder

BMI is a good guide and in general you can calculate the percentage body fat based on the BMI, but there would be differences for each person.

Yeah, pretty much.

Unless you are pretty athletic it is a reasonably valid measure of body fat percentage:

http://www.ncbi.nlm.nih.gov/pubmed/2043597

LOL

The calculation on there said that I have a BF% of 20%! HAH! That's off by nearly 15%! I have a BF% of 35!

How did you obtain your BF% as 35 out of curiosity? From the stats you gave in OP you should have a BMI of about 30 which equates with a rough BF% of about 26-27.

I'm not saying that this is right or that calculation holds true for you but it does seem a little unusual.

I use a body composition monitor which has been rated to be accurate within 2% +/-.

If my current BF% were 26-27%, then my UGW would be even higher, making me even further out of the "acceptably healthy" range.

myofibril

I use a body composition monitor which has been rated to be accurate within 2% +/-.

If my current BF% were 26-27%, then my UGW would be even higher, making me even further out of the "acceptably healthy" range.

Handheld monitor? How many pads does it have?

For you certainly BMI isn't really a good guide but that makes me wonder if you aren't a formerly athletic individual...(ETA: just read your profile...)

chivalryder

It has foot and hand grips. About 10 pads in total.

I used to ride a lot 4 or 5 years ago. I'm sure my fat and muscle composition has changed a decent amount in those years. Since my injury, I've basically spent my entire life sitting on my butt.

iuew

the scale is flawed if you're a bodybuilder. for most other people, it works pretty well.

no one measure is all inclusive. when choosing my goal weight, i used BMI and the metlife tables from the 1940s. i'm fairly happy with the result.

drdebbiejo

I agree that the BMI is limited - but it is a general guideline for patients looking to find out what is appropriate - particularly to confirm that a BMI of 13 or 14 (think your average model) is really really UNHEALTHY, or to see if you are dramatically above the recommended range. I think it would be better to say you should "APPROPRIATELY" use a BMI.

I think that society's fixation with looking a certain way and obtaining a particular BMI is very dangerous. A lot of my patients newly diagnosed with cancer come to me saying that they were excited that the weight was finally "melting off" of them - when what was happening was a life-threatening illness. I never congratulate people for being "thin", only for trying to be more healthy. I have a lot of unhealthy thin patients and pretty healthy "overweight" patients.

That being said, obesity is certainly associated with a lot of health problems and makes medical treatments, such as surgery and chemotherapy, more complicated, and we have frighteningly high rates of obesity in North America that are reflective of poor lifestyle choices and cultural programming.

Because it is a range, a BMI can be a helpful guideline to what is "average" in a healthy population. Like any guideline, however, it is only that, and at the end of the day if you are metabolically healthy, physically active, and emotionally strong, you are in great shape - no matter what anyone else thinks or what your BMI is!

myofibril

It has foot and hand grips. About 10 pads in total.

I used to ride a lot 4 or 5 years ago. I'm sure my fat and muscle composition has changed a decent amount in those years. Since my injury, I've basically spent my entire life sitting on my butt.

Fair dues. It sounds like a decent enough monitor and barring unfavourable test conditions (not leaving enough time after eating / drinking / exercise, hydration levels etc) or malfunction it should be mostly accurate.

I do find it very surprising that your BF% is so high though despite your recent weight gain. It seems accelerated. However, the amount of muscle you are carrying may have not have lowered as much as imagined simply because you have something quite positive in your favour ~ your high body weight. Simply lugging it around will have some preservation effect given the stress it imposes on your muscles. That's one of the ironic things about obesity in general : obese people have higher amounts of muscle mass then they imagine without ever having set foot in a gym...

Anyway, BMI doesn't seem suitable for you as an individual clearly.

Good luck with your goals

Raducan

It's also stupid because it's used in relation to people with eating disorders: you cannot have an official diagnosis of anorexia when your bmi is above 17.5.... as a large built person I would be dead before I got to that point. I know people with BMIs of 20+ who fit all the other diagnostic criteria for anorexia but would never be treated because they are too 'fat' even though in many cases they are all bone.

chivalryder

It has foot and hand grips. About 10 pads in total.

I used to ride a lot 4 or 5 years ago. I'm sure my fat and muscle composition has changed a decent amount in those years. Since my injury, I've basically spent my entire life sitting on my butt.

Fair dues. It sounds like a decent enough monitor and barring unfavourable test conditions (not leaving enough time after eating / drinking / exercise, hydration levels etc) or malfunction it should be mostly accurate.

I do find it very surprising that your BF% is so high though despite your recent weight gain. It seems accelerated. However, the amount of muscle you are carrying may have not have lowered as much as imagined simply because you have something quite positive in your favour ~ your high body weight. Simply lugging it around will have some preservation effect given the stress it imposes on your muscles. That's one of the ironic things about obesity in general : obese people have higher amounts of muscle mass then they imagine without ever having set foot in a gym...

Anyway, BMI doesn't seem suitable for you as an individual clearly.

Good luck with your goals

I measure myself every morning, first thing after I wake up in the morning, and go to the washroom. I don't even drink a glass of water first. My results have been very consistent.

peachyxoxoxo

It's also stupid because it's used in relation to people with eating disorders: you cannot have an official diagnosis of anorexia when your bmi is above 17.5.... as a large built person I would be dead before I got to that point. I know people with BMIs of 20+ who fit all the other diagnostic criteria for anorexia but would never be treated because they are too 'fat' even though in many cases they are all bone.

I don't think that's in the DSM. The only numbers involved in diagnostic criteria for anorexia nervosa are body weight less than 85% of expected weight. Additionally, it has been proposed that this particular stipulation be removed from the definition.

crisanderson27

I'm sorry but body builders and elite athletes are not part of the average population. By the time someone is in that category they do not need an instrument for the average population as a guideline. Look around you--the average person is overweight or obese. many will read this and say--well BMI means nothing--I'm just big boned and not obese.
It is not pleasant t look at the chart and see that you are obese--but it is a wake up call. It is frustrating to lose weight and still be considered overweight. For those of you who are elite fit, you are at the point where the number on the scale means less than your body fat %.
BUT the average person should not toss out BMI because it gives a large range of what is considered healthy. To just toss it out is to stay in denial.

Body builders? Elite athletes? Seriously?

Here, look at this picture:



Does that look like a body builder or elite athlete? I see a guy who is about 18% bodyfat, 5'7" tall, and BORDERLINE OBESE by that stupid chart. That guy had a doctor tell him that he STILL needed to lose weight (while he was standing there with his shirt off btw) because of his BMI number when he had his bloodwork done for a circumstance unrelated to health.

So...when the medical field, and insurance companies stop judging INDIVIDUALS by this 'tool' designed to look at 'averages'...then people like myself will stop ranting about how useless it is.

Until then, it's flawed, and next to useless for a good chunk of the population.

No thanks.

Merithyn

I'm sorry but body builders and elite athletes are not part of the average population. By the time someone is in that category they do not need an instrument for the average population as a guideline. Look around you--the average person is overweight or obese. many will read this and say--well BMI means nothing--I'm just big boned and not obese.
It is not pleasant t look at the chart and see that you are obese--but it is a wake up call. It is frustrating to lose weight and still be considered overweight. For those of you who are elite fit, you are at the point where the number on the scale means less than your body fat %.
BUT the average person should not toss out BMI because it gives a large range of what is considered healthy. To just toss it out is to stay in denial.

Body builders? Elite athletes? Seriously?

Here, look at this picture:



Does that look like a body builder or elite athlete? I see a guy who is about 18% bodyfat, 5'7" tall, and BORDERLINE OBESE by that stupid chart. That guy had a doctor tell him that he STILL needed to lose weight (while he was standing there with his shirt off btw) because of his BMI number when he had his bloodwork done for a circumstance unrelated to health.

So...when the medical field, and insurance companies stop judging INDIVIDUALS by this 'tool' designed to look at 'averages'...then people like myself will stop ranting about how useless it is.

Until then, it's flawed, and next to useless for a good chunk of the population.

No thanks.

I think I love you.

:smooched: :flowerforyou:

rhinowithonehorn

I judge my UGW based on my current lean mass + a certain BF%. I was going by 15%, but decided that I should slow it down a bit and increased that number for a "One-step-at-a-time" goal. Once I've built up my fitness, then I'll aim for a lower BF%.

So I did the numbers. A healthy, relatively inactive male should have a BF% of 18-25%. 21% is half way in between, so I chose that as my goal.

I got the numbers from here: http://www.bmi-calculator.net/body-fat-calculator/body-fat-chart.php

I currently have a BF% of about 35%. At 223 lbs, that makes my lean mass around 144 lbs. Put on enough fat to make it 21% fat, and my UGW is 179 lbs.

Well, I'm 6' tall. I checked out the BMI scale, and at that weight, I will be hitting 24.27.

"Overweight" is higher than 24.9.

Now, here's the thing: If I put on 2 lbs of muscle before I reach my UGW, I'll be 185 lbs, which is considered "overweight," but it'll be less healthy for me to try to achieve a lower BF% so quickly!

I will ultimately aim for a BF% of 10-15%, but by that time, I'll have put on a lot more muscle, I will probably still be around 180lbs.

So, for those of you who believe that you need to have a low BMI in order to be healthy, or sexy/attractive, you may want to think again. The BMI scale is flawed.

Oh, and I should note: I could make my BMI lower, but I'd have to lose lean mass. For those who aren't in the "know," that would be a very, very bad idea. You want more lean mass, not less. Lean mass being your muscles, bones, and organs.

Edit: Added the link.

Not true it is quite accurate. If you are a body builder or havce some type of rarer boen structure it possibly will be wrong. Other than that for 90 percent of the population it works. the thing is being 10-30ibs overweight doesn't automatically make you unhealthy or look fat but ideal is within the accepted bmi range.

And when you lose weight it is impossible to maintain 100% lean muscle mass. The body will go after both but far more fat than muscle.