Is BMI accurate or misleading?

[msk01kxx]

Some people rely on Body Mass Index (BMI)
Which is a measure of our weight in relation to our height


But is BMI really the best measure for weight/body fat?
Is it a good way to tell if someone's weight is healthy?

Or is it Bogus?
Its far from a perfect measurement and its not an accurate measure of health?

Misleading/inaccurate

Accurate

[Anonymous]

The BMI is highly misleading and scientifically bankrupt. You are right to question it.
At its most basic, BMI is a random mathematical combination of height and weight. There is no physiological basis for the formula, it is entirely random. Prima facie, that should be enough to ignore it.
However, a second major issue with BMI, and one that is never discussed, is the blatant fraud of "percentiles". The definitions for "obese", "overweight", etc. for persons 19 and under are defined directly in terms of percentiles of that age group. Adult BMI is indirectly defined the same way. The fraud here is that such percentiles are based on data collected before we landed on the moon, which is of course out of date. In any other instance, using such outdated data would be unacceptable, but it is maintained with the BMI because it allows the mass body-shaming of people. As a stat project, I once made a modernized BMI that corrected this error, and surprise surprise it does not give so many dramatic fear inducing predictions.
The BMI however stays around anyway because it serves as a useful tool for several vested interests. These include a multi-billion dollar weight loss industry, a seedy iron triangle of regulators, the healthcare industrial complex, and various academic research interests that get big grants by predicting disaster. The anorexia obsessed fashion industry and media industrial complex is all to happy to go along with this as a way to shame anyone who is not supermodel thin.
So in a nutshell, the BMI is not worth a plug nickel and has permanently damaged the lives of millions of people, especially young girls, by teaching a dogma of fat shaming and eating disorders as gospel.

[PrimalInstinct]

It's misleading & inaccurate for a variety of reasons.

1) BMI doesn't take into consideration bone mass. More bone = greater weight. You tell your bone mass by measuring how thick your wrist is. For my height (5'2") the averaged big-boned wrist is 6.75 cms (thin is 6 cms). My wrist, with the tape pulled tight, is 7.10 cms.

2) Muscle mass. Muscle is denser than fat. No not heavier (a pound is a pound) it takes up less room in the body than fat. That's why someone can be muscular & active yet can still be as "obese" as someone who sits on the couch all day watching tv with a bag of chips & a 2l of pop. I'm very active.

Apparently, though I'm "very obese". I'm not. I don't even look fat. I look powerful/strong. It's why friends joke I'm "built like a tank".

[Obtuse]

It's a very crude predictor of health risks as I see it. It doesn't account well for trained individuals for a start with increased lean mass. For example, Mike Tyson in his prime was over 30 BMI and, according to BMI criteria, "obese":

... Yet that's hardly the type of body susceptible to the likes of type-2 diabetes.

It also doesn't account well for race/ethnicity. For example, Asians often have lower bone density and muscle mass on average, so they can be quite light in weight and small in spite of having a fairly high body fat percentage. This is why a lot of Asian countries adjust the BMI criteria to consider anything greater than 23 BMI to be "overweight" instead of 25 BMI as in the West. It's not due to a stricter standard; it's due to a difference in genetics.

Anyway, it's all very crude. I've even seen medical professionals cite the height-to-waist ratio as a superior criterion to BMI for predicting health risks. A large part of this might be due to how visceral fat in the abdominal cavity that surrounds organs is often the most tightly correlated with many of these health risks. Body fat percentage is probably the best indicator, especially when it breaks down where the body fat is distributed and whether it's subcutaneous or visceral.

[genericname85]

it's a bit missleading, cause it doesn't make a difference between muscle and fat... so if you're buff, you will be counted as "obese"... even if you're completely shredded with no body fat.

[jgokgotit]

The military uses BMI in their fitness assessment but it is not the final factors. Most Navy SEALs would fail by weight alone because of the way they are built.

[genericname85]

@jgokgotit I know the struggle. I build muscle really fast naturally. So every time I decide to lose weight and hit the gym, I gain muscle mass faster than I lose fat.

[aicarg]

It's not an ideal diagnostic tool as BMI does not take into account age, gender, or muscle mass. Nor does it distinguish between lean body mass and fat mass. As a result, some people, such as heavily muscled athletes, may have a high BMI even though they don't have a high percentage of body fat. In others, such as elderly people, BMI may appear normal even though muscle has been lost with aging.

I've done a weighing for my body fat percentage before using hyhydrostatic weighing - where I had to breathe out as much air as possible and submerged myself in water. It was done in a kinesthetics class I took in university.

[LiamSawyer]

It may work accurately for a percentage of the population but if you have a large from with high density bones and a good amount of muscle it's way out of line. Bones and muscle are much heavier than fat. I've seen cases where a very lean well built person with a large frame according to BMI is 20 to 30 pounds overweight.

[aaa9501]

I think BMI is good for what it's used for. We don't use it for accuracy, we use it because it's easy to use and it's a good screening tool for medical professionals. It's generally pretty reliable for the average person (not really muscular bodybuilders). A lot of chronic conditions and diseases are actually correlated with higher BMIs, so for a doctor who wants to see if their patient is at a higher risk of developing a disease, let's say type 2 diabetes, they can calculate their BMI instead of having them do a complete body composition test.

[Unit1]

Body Mass Index should be taken as one of the factors of determination and not a definite answer to the question whether you are healthy or not or whether you are malnourished or obese.

Bodybuilders weigh more because muscles weigh more than fat.
And athletes may keep their shape and their weight rather low for purposes such as duration during sports, which may involve keeping diet to the level of being lightweight.

These are not ultimate answers.

[SuccessfulHornDog]

I would never say that it is accurate and it can be misleading or even very misleading. I was at a health fair a few years ago and I was in awesome shape, very muscular and lean with a body fat percentage of 10-12%. One of the people working at an exhibit asked me my weight and height and then proceeded to tell me in a alarmed voice that I was obese or higher. I have always had more muscle than my peers and muscle weighs 200% of what fat does so my BMI can be misleading even on a good day. At the time I was running 30 miles a week and lifting weights eight hours a weeks and I was jacked. BMI can also be misleading in the other direction. Someone can be known as skinny-fat. They dont weigh much because they dont have much muscle but they aren't healthy because of the body fat percentage is really high. The BMI chart may show them as normal but theyre not.

[Flower7]

BMI is very misleading because bodybuilders or other people who work out a lot are full of muscle, which is really heavy. That makes their weight go up, and the next thing they know, they're being categorized as overweight or obese, even if they have an extremely small body fat percent. The problem with BMI is that it doesn't differentiate between different types of weight.

[TheUniqueOne96]

It's a decent guide, but it's not a good indicator of overall health, because it doesn't take into consideration what a person's weight consists of e. g. you could be overweight according to your BMI, but if you have like 10% body fat and a lot kf lean muscle, then based off of them alone, you should be fine, as overweight does tend to refer to excess body fat.

[meesegoMoo]

For women it can be alright. Men are a tad too varied. It works better for old men though. Really it's just men under 60ish that can't really use it.

If it says morbidly obese I would take that seriously. In the extremes I would trust it for underweight/overweight, the composition of that weight matters less in those cases.

[TallAnon]

It's really just an average indicator. The less average of a person you are, the less it makes sense. Tall, short, muscular, etc.
For a much better indication, look at fat percentage.
BMI would tell me that I'm super obese, but I am very tall and have some muscles, fat percentage tell me I'm healthy.

[Godofbliss]

If you're a person who goes to the gym or alters his/her body muscle/fat percentages for any specific reason. Then BMI is misleading. It's mostly meant to classify a normal human with no specific body recomposition into a set criteria and this determine if they are at risk for diseases. If you're using it for any other purpose. For example, to see muscle growth/fat loss after a body recomposition process, it would be grossly misleading.

[Kurαȷ]

It's not accurate for bodybuilders, athletes and others with significant differences in lean body mass.
It's accurate for everyone else, because everyone else doesn't have significant differences in lean body mass.

[HerLucidNightt]

Super inaccurate. Weight and BMI don't correlate. If they did, Dwayne the Rock johnson is a fat fuck.

[hamadazopry]

It's important to track ur BMI and always maintain it between 18-25 however this doesn't mean u have an attractive body shape, u need to track your fat/ muscles ratio through an inbody test and to measure the body different parts, arms/ waist/ hips or thighs, by this u can be sure you've got the perfect body shape

[Curmudgeon]

Definitely misleading. I was a rail thin teenager and I was 6'5" and 180 lbs (1m98cm and 82 kilos for you metric people) and I was considered "Normal". Jeez, to attain their "healthy" weight I would have had to be in a concentration camp.

[AaronKrieger]

It can be accurate, but it also always isn't. It doesn't account for how much muscle someone has or how their fast is distributed throughout the body.

[Michael510b]

The body mass index was commissioned by the health insurance company to charge higher premiums to different people.

It was denounced by its very author as being inaccurate and immoral.

[LoU_Hades]

For men with higher muscle mass it's not accurate. Tall and slender girls are often below the green scale despite normal body fat.

[Goiiae]

I think for most people it’s a useful tool, only isn't accurate when used on muscular people. It predicts risks of illnesses tied to excessive body weight aka fat

[baseballnerd24]

I would say that it is misleading because it can't differentiate between someone being 250 pounds of muscle vs someone being 250 pounds of fat. However, I think that most people are well aware of whether or not their BMI is mainly muscle or fat.

[RonJon20]

BMI is a fair representation but a scale that also shows % body fat is better

[Liam_Hayden]

It is garbage for body fat %. I'm 6'2 and just about 200 lbs. According to BMI I am overweight. Except my body fat % is between 10% and 11%.

[Apple1996]

It isn't accurate for me since I'm soo short. I'm sure it not accurate for a lot of other people too

[Itsme1999]

It's not that when you have a good bmi you are healthy. People always assume that a good bmi means that they are healthy. Exercising is really important to be healthy.

[ultimega]

Yes it I'd as it's a very broad indicator.
Not including those who have a higher percentage of muscle and bone density

[Matt57]

It’s misleading and inaccurate. I learned in my contemporary health class that Water Displacement is the most accurate form of measurement.

[Aaron_Stone]

Its just measure you can add deviation to it according to your standard.
The thing that matters is how you look and how fit you are.

[COMMODOREII]

It is actually misleading i was told by the hospital i worked at that they are working on better indicators.

[TacosRAwesome]

Accurate for the average person, not so much for people with a high muscle mass.

[gruvman]

It's misleading because if your weight is over but because of muscles then you're in a good condition

[Lunatic1]

It is misleading. It says I'm obese but I don't look bad.

[kim45456]

Hahahahahahagahahahagahaha

[Prettyapathetic]

Yeah he doesn’t look obese

[Lunatic1]

Thank you very much. Lol.

[Snakeyes7]

For the most part misleading. I don’t think it takes muscle mass into account.

[Cryptic-Game]

Mostly misleading. It takes very few factors into consideration.

[Nickel_Slam]

Misleading mostly. It doesn't take a lot of factors into account.

[Prettyapathetic]

The third lady doesn’t even look fat

[Razal]

It’s a pretty good measure

[bklynbadboy1]

Accurate