What is the Body Mass Index and is it the best measure of obesity? - CrowdScience, BBC World Service

[@Pou1gie1]

@14:00 In Tonga, and with many colonized countries, the issue is that they aren't eating their traditional native foods anymore. I have heard stories of native Alaskan ppl being sick on western foods going back to their native foods and after months to years they no longer have diabetes, high blood pressure, etc.

[@ravindra7791]

Yes... specifically I understand Australia (and NZ) have sent low cost meats of cuts that they don't eat to the Pacific islands. So that is a cause too.

[@shyft09]

the trouble is modern western foods are more delicious (salt, fat , sugar, msg etc) and cheaper to produce

[@petervince167]

I think waist-to-height and waist-to-hip ratios are better predictors of obesity risks. Clinical tests such as complete blood count, blood pressure, and other tests are more useful than bmi and the ratios mentioned above.

[@stuartneil8682]

So at just over 6’ and 75kg I look skinny but have non alcoholic fatty liver disease. This despite running and some weights and feeling healthy at age 62. When In was slightly overweight according to BMI then the last time at 85kg it was less excercise and more biscuits, however I’ve been that with earlier in life with consistent work in the gym so it illustrates the points that you are making, that it’s a poor measure of my health.

[@now4itfriends]

Thank you so much, this was an excellent overview 👌🏻

[@marathorne6821]

It's a "cheap and cheerful" measure. Body fat composition is not accessible to everybody at home. Too much fat, particularly visceral fat, compromises health. BMI is far from perfect, but it's a starting point for further investigation.

[@careylee2595]

How about waist hip and waist height ratios?

[@laurachristianson1688]

This too is problematic as short waisted people’s waist measurement is closely related to their hip measurement, there’s only so much area you can squish your internal organs into….

[@dinimueter539]

I think the BMI is a fairly good guideline for most people. It’s not perfect of course but I don’t get some of the criticism. Come on, everyone knows if they are more the type „bodybuilder“ or „couch potato“. And your doctor can see it. Serena Williams knows she’s not overweight but very muscular. I don’t like how the guy from Tonga sugarcoats Tonga‘s high obesity rate. There’s a difference between larger build and obesity. In Tonga 13% of the people aged 20-79 have diabetes type 2. I watched a documentary about Nauru and how the obesity rate of its population skyrocketed after industrialized countries ruined their environment and started to supply them with cheap ultra processed foods. We need to address this issues instead of sugarcoating obesity. If you want to help marginalized people you need to find out why they are obese instead of claiming that by addressing the issue you are being racist.

[@campflint76]

We know that visceral fat is the real problem- too much increases the risk of a range of diseases. BMI is a rough but sometimes inaccurate screening tool for excess visceral fat. Not many people can afford an accurate but expensive,say, DEXA scan. That said, by the time one’s BMI is in the obese category, unless you’re a professional bodybuilder, you know you likely have too much visceral fat. No shaming here, just a medical condition to be addressed.

[@mamakaka73]

People need to grow a spine. Admit it. You are fat. I am fat. Life is not all rainbows and unicorns.

[@BartBVanBockstaele]

I agree. While I no longer am fat, I have always demanded the right to be called what I was: fat. Changing the wording does not change the fact.

[@applejuicejunkie316]

It's not about spine. BMI tells underweight people they're OVERWEIGHT. BMI also isn't indicative of overall health. Skinny people have TERRIBLE health simply because society says they're in shape. Bob Harper, a fitness instructor on BIGGEST LOSER, nearly died from a heart attack. BMI is a pseudo-science used to fat-shame.

[@lazyhunk2]

Fatphobia is the root of racism.

[@LarryDiamond-te3yt]

2:12 one of the biggest issues is this: ‘my neighbors can eat what they want’ and they are thin. At minimum 50% of people, that are ‘normal’ BMI are significantly insulin resistant if not raging type 2. We each have a ‘personal fat threshold’. Someone can have a BMI of 40 and less visceral or organ fat than someone with a 23 BMI. TOFI. Thin outside, fat inside. But there is no health at every size. Too much adiposity even in safe subcutaneous fat, creates chronic inflammation. So it’s the case in today’s world that many ‘normal’ BMI are as obese as the rest of us that can actually get obese. I did reverse my morbid obesity. Noting fancy: tasty real food, intermittent fasting, falling in love with natural fat and salt. Not sexy, super effective. But don’t chase weight loss. I was interested In health. When I found out I could eat steaks and broccoli lathered in butter, my success was assured: Focus on transforming relationship with food, getting healthy, move better, sleep better, fast better. The weight loss follows 🥰🌞🥰

[@timosnieder4637]

I agree. Focus on health and wellbeing, not weight loss.

[@yucalin3000]

0:23 Isn’t it weight divided by square meters of height?

[@pynn1000]

May have been in metres for the original BMI tables, but "cm" are more used for metric measurements of height e.g. all online metric calculators ask for measures of height using "cm".

[@YPNOBATHS]

I was 102 kilos and with health of my dietician I reach my normal BMI . It's important to understand that you should be educated by career how to combinate the food. There's no meaning to be slim and to eat harmful products . Or your goals are only to lose your weight.

[@asrafuldigital1247]

Nice very helpful video i am from India

[@shyft09]

Some countries use WHR and that seems to make much more sense, I think Japan does. Belly fat is a real killer, fat on your thighs (for a woman) is not

[@pynn1000]

WHtR (or WSR with S for "Stature") is cheap, simple, works with a simple sum. UK officially adopted it as a better measure than BMI nearly 2 years ago (but I don't know if it's widespread yet). Japanese, other researchers have shown that it works with varied ethnic groups and ages.

[@marathorne6821]

The word "diet" is now used to mean some (often faddy, drastic) short-term weight loss intervention that people either can't stick to at all, or cannot wait to revert back to their previous eating patterns - hence their high failure rate. If you adopt a healthy but satisfying eating pattern with a view to sticking with it FOR LIFE, you'll be able to keep the excess weight off once you've lost it. I believe the biggest enemy nowadays is ultra processed food, scientifically designed to encourage over-consumption of unhealthy chemical substances masquerading as food. It's really difficult to avoid consuming this stuff, it's ubiquitous and looks like the real thing (until you read the ingredient labels) but it's worth trying. "Garbage in, garbage out" doesn't just apply to computer programs.

[@samuelstephens6904]

While agree with most of what you said, the reason people are fat is not because of “unhealthy chemical substances masquerading as food.” Food that is “ultra-processed” usually just has a ton of added fat and sugar for the sake of palatability. Fat and sugar are perfectly normal nutrients i.e. real food. But like all macronutrients, they come with calories. If you consume too many calories every day, then you will become fat. So there is nothing qualitatively different about processed foods. They simply tend to be more energy dense and thus lead to overeating.

[@la6640]

I think waist should be measured against the hips ratio. Legs and arms are healthly when they are big specially if it's mostly muscle mixed with fat.

[@TheKarlgiovanni]

Nice interview.

[@iambeiam]

There had been so much fuss about BMI so much so that people become obsessed by it. But a low BMI is misleading. A regular consultation with one’s practitioner coupled with full bloodwork will help assess one’s health situation better. I for one has always had a low BMI only to find out my blood markers show otherwise; thin on the outside but “fat” on the inside. I find a regular check with my GP is more beneficial in catching underlying health issues early enough thankfully.

[@aroundandround]

0:24 At least learn what to divide by what.

[@Ashinjotipala-m9h]

well done❤

[@BartBVanBockstaele]

As the video says: BMI is not and was never meant to be a measurement of health. Anyone who does that anyway, does not really know what he/she is doing. As is popular in computers: RTFM. That is always good advice.

[@samuelstephens6904]

BMI kind of is a measure of health though. It’s like blood pressure. No, it doesn’t offer a look at someone’s entire health profile. But being too high above or below the healthy weight range does provide some insight about a person’s health and what risks they have.

[@BartBVanBockstaele]

@@samuelstephens6904 Many people think that, but it is dead wrong. BMI is a population-level classification. It is used for studying populations, not individuals. It is not needed at all for individuals. A doctor who has normal eyesight can diagnose fatness by looking at her/his patient. IF a weight gain/loss treatment is started, monitoring the weight of the patient will tell all the doctor needs to know about its effectiveness. People who use BMI as a diagnostic tool have fallen asleep during their statistics class at med school.

[@samuelstephens6904]

@@BartBVanBockstaele -"It is used for studying populations, not individuals" BMI is definitely used to screen individuals, not only to look at populations. Again, it's like blood pressure. If you have BMI over 30, you are in a sense objectively unhealthy.

[@samuelstephens6904]

@@BartBVanBockstaele BMI is used to screen individuals though. Imagine the only thing you know about a person is that they have a BMI of 85. Would it be fair to conclude that this person is unhealthy? Of course!

[@BartBVanBockstaele]

@@samuelstephens6904 Screening is done at a population level. Insurance companies like it for exactly the same reason. That's what BMI is for. It is not a diagnostic tool. A doctor who looks at a person with a BMI of 85 and can't diagnose fatness by looking at that patient is not a doctor but an outrageously incompetent individual.Think of it: a 1.8 m person with a BMI of 85 weighs 275 kg. You don't need a BMI number to know that person is fat.

[@galactic_socialist]

Remember Arnold Schwarzenegger had a BMI of 31 during the peak of his bodybuilding career My physician doesn't buy into BMI but has to record it to get payment from the insurance company

[@CatholicSatan]

Oh yeah, 'cos _so many_ people are elite body builders.... BMI is a good indication for the vast majority of people.

[@bk2no]

Steroid use will allow you to put on more muscle than the average man. As stated in the video, muscle weighs more than fat. BMI is a good indicator for most normal people. You can also just look in the mirror. If you have a big gut, you’re overweight.

[@cassieoz1702]

Obesity is overfat, not overweight. Even the use of BMI as an indicator of survival has aggregated all ages when, if you plot BMI by age, what are 'healthy' BMI ranges varies. Slightly higher BMI predicts longer life in over 60s.

[@samuelstephens6904]

>Slightly higher BMI predicts longer life in over 60s. No it doesn’t. The reason this merely appears to be the case is that the older you are, the more likely you are to contract a fatal illness that will cause you to lose weight before the end e.g. cancer.

[@cassieoz1702]

@@samuelstephens6904 it still plots survival correlation

[@samuelstephens6904]

@@cassieoz1702 But correlation doesn't equal causation. The takeaway from this should not be that having a higher BMI means you are more likely to live longer because that is false. What actually explains the correlation is people dying of certain diseases where weight loss is a symptom, diseases which *overweight people are at a higher risk for and will have a harder time surviving!*

[@cassieoz1702]

@samuelstephens6904 oh, I understand about causation vs correlation but, from my reading, it's still not useful to draw 'common sense' explanations as to why. It could just be the survivor "I managed to live until age 70" bias

[@samuelstephens6904]

@@cassieoz1702 It’s not a “common sense” explanation. When you account for people losing weight from fatal diseases, people who are overweight do not live longer than people who are at a healthy weight. This is a fact.

[@shyft09]

When it comes to doctors advising their patients to add or loose weight as a result of their BMI number (as they do unfortunately) it can be disastrous for someone who it doesnt apply to. People trust their doctors

[@samuelstephens6904]

If you have a BMI over 30, then there is a 99% percent chance you are too fat and will be healthier if you lose weight. There is a 1% chance that you are a dedicated bodybuilder taking steroids. If you are in that 1%, then it will be extremely obvious to you and your doctor.

[@BBCWorldService]

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[@ALEJANDROHERNANDEZRUIZ-s1d]

"you ate your way in, you can walk your way out" Bill Burr

[@chrisengland5523]

BMI doesn't make any sense to me. It would do if it were mass / height cubed rather than squared. Why? Because with the current definition, it is skewed in favour of short people. Here's a hypothetical situation to explain this: Consider two people, one is 1 metre tall and the other is 2 metres tall. Also, and this is a KEY POINT the two people are proportioned exactly the same - in other words, the tall one is a magnified version of the small one. Assume that the short one weighs 20 kg. So let's calculate their BMI's, which is the weight in kg divided by the height in metres, squared. The BMI of the short guy is 20 / (1 x 1) = 20 kg / m2. (A supposedly very healthy value.) To calculate the BMI of the tall guy, we need to work out his weight. Remember, he has exactly the same proportions as the short guy, so if he is twice as tall, he's also twice as wide (side to side) and twice as thick (front to back). So his 'volume' will be 2 x 2 x 2 that of the short guy and therefore his weight will be 20 x 2 x 2 x 2 = 160 kg. His BMI is therefore 160 / (2 x 2) = 40 kg / m2. So the tall guy has a BMI twice that of the short guy despite the fact they are both identically proportioned. Why does simply being taller but identically proportioned lead to a higher BMI? An identically proportion person will have all the vital organs and fat etc. in the same proportions as the short guy - yet, the BMI says he's unhealthy. It doesn't make sense.

[@swimmerboy172]

You are wondering why the person that is 2x as tall but 8x the weight has a higher BMI? Seems kinda self-explanatory

[@chrisengland5523]

@@swimmerboy172 Yes, that's what the maths tells us, but the point is, it doesn't make sense. Someone who is twice as tall SHOULD weigh 8 times as much otherwise his proportions are wrong: twice as much because he's twice as tall, twice as much again because he's twice as wide (from side to side) and twice as much yet again because he's twice as thick (from front to back). And 2 x 2 x 2 = 8. If he's not 8 times as heavy, his proportions are wrong. Think in terms of a cube, 1 x 1 x 1 metres and assume it weighs 1 kilogram. It's BMI is 1/(1x1) = 1. Now stack 8 of these cubes together to make a larger cube 2 x 2 x 2 metres. This is just a larger cube but apart from that its properties are identical. Everything is in the same proportion, so if it were somehow alive it would be just as healthy, but its BMI is 8/(2x2) = 2, ie. twice that of the single cube. So the question is why is BMI measured as weight/height squared, rather than weight/height cubed? Either whoever invented BMI is hopeless at maths or there's some factor that I (and most others) don't appreciate as to why it's the way it is.

[@zlinos139]

What!? It makes perfect sense,if you are 2 m tall and 160 kg weight,you are not healthy obviously

[@chrisengland5523]

@@zlinos139 Your missing the point. It's the RELATIVE figures that count. If it helps, rework the figures with lighter people, starting with the tall guy. Assume that the 2 metre tall guy weighs 80 kg. His BMI is 80 / (2 x 2) = 20, which is a healthy figure. Now scale him down to 1 metre in height to get an identically proportioned short guy. The short guy will weigh 80 / 8 = 10 kg and his BMI will be 10 / (1 x 1) = 10, which is far too low. Why? He has the exact same proportions as the tall guy and his weight is in the same proportion, but the BMI calculation leads to absurd figures.

[@zlinos139]

@@chrisengland5523 Are you saying that in your calculations a person weighs 10kg and you want me to take your comment seriously?

[@Mloda-br3br]

I eat normal dont do diet and hot the hell 😢 I m keep losing my weight? Need done some blood test

[@gergohavasi7902]

I think it's another way not to take responsibility for our choices and actions. I especially dislike the argument that bodies come every shape size. Historically humans never had constant access to this amount of food. Preserving fat was a tool to survive famine, which occured regularly. Now it's on us to say no to excess food, as our body is not smart enough to do so

[@timosnieder4637]

Which is a more significant problem: the stigma around being obese, or the obesity itself?

[@samuelstephens6904]

Obesity.

[@hummerhummer2567]

Been to over 10 funerals never have I had any one complement a dead body having a good physique

[@Pietro-th1yd]

As far as I know, dieting has a high failure rate because, often, it is practised without the aid of a professional...

[@laurelledubois]

The vast majority of them haven't got a clue themselves. Failure is due to wrong eating patterns/no willpower and our hormones failing us.... The problem is: if the right eating habits are not taught at home from childhood, it it very hard to un-learn them in adult life... Also most people haven't got a clue what "healthy eating" actually means...

[@Pietro-th1yd]

So you seem to agree with me on the fact that this episode send a wrong message about dieting.

[@BartBVanBockstaele]

Not just that. It is also a matter of self-knowledge. I have struggled with my weight for over 40 years. Nothing worked... until I accidently found a way of eating that made it possible to be **less** hungry. Willpower did and does the rest. As a result, I lost well over 60 kg and am keeping them off.

[@Pietro-th1yd]

The wrong message this episode conveys is that because of its high rate of failure dieting is not a reliable method to control your weight. I'm there a more people who quit the gym rather than people who keep up exercising, however, working out is undisputably beneficial...

[@BartBVanBockstaele]

@@Pietro-th1yd I wholeheartedly agree. Just because people don't do A is a nonsensical reason to say that A doesn't work.

[@Lovely-DeeM]

BMI is a very flawed measure of anything, there was a pastor in the church I go to, who once stood on the pulpit (he is pretty tall and lanky and middle aged, so no muscles or athletic body to say that the BMI calculation took his muscle mass as fat), and the BMI calculation stated that he was obese which is ridiculous. He was joking about it on the pulpit. Ever since then, I realized that the BMI measurement is not accurate at all, and should not be used in any medical institution to determine obesity.

[@samuelstephens6904]

Nah. Either your pastor is fat or miscalculated his BMI. The average American adult male has a BMI of 29. Obesity starts at 30. So obesity tends to look pretty “normal” to a lot of Americans because they are use to seeing it.

[@yongbinsong9676]

BMI is not proper to identify the degree of health.

[@pynn1000]

Useful at a large level to see changes within a population, or (with caveats) to compare countries. I agree that it doesn't tell us much about individual health.

[@timosnieder4637]

I dont think that was ever its goal, as per the host.

[@garrett7101]

Muscle phobic for sure

[@user-rw8qt7jf3q]

You're fat in your pic lol

[@jovsta]

1.9m is 6 foot 3.

[@JanetLClark]

Ugh Ansel Keyes, champion of cereals :p