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  Reply # 1960895 20-Feb-2018 12:03
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MikeAqua:

 

sidefx:

 

BMI doesn't mean much without knowing a persons fat percentage.

 

 

Based on direct and recent personal experience ... BMI means enough to be used as a qualifying criteria for some surgeries.

 

The relationship between BMI and % body fat is tight for example this study

 

 

Maybe for Sri Lanka with a uniform ethnic and socio-economic demographic... but not so sure for New Zealand with a more diverse ethnic and socio-economic makeup.

 

I, am surprised for surgery that they'd bother with it given there would be various physical examinations and tests before the surgery anyway that are more accurate.

 

BMI is a pretty rough measure. Any mesomorph or athlete with muscle mass will most likely come out as overweight.

 

 


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  Reply # 1960928 20-Feb-2018 12:52
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kryptonjohn:

 

MikeAqua:

 

Based on direct and recent personal experience ... BMI means enough to be used as a qualifying criteria for some surgeries.

 

The relationship between BMI and % body fat is tight for example this study

 

 

Maybe for Sri Lanka with a uniform ethnic and socio-economic demographic... but not so sure for New Zealand with a more diverse ethnic and socio-economic makeup.

 

I, am surprised for surgery that they'd bother with it given there would be various physical examinations and tests before the surgery anyway that are more accurate.

 

BMI is a pretty rough measure. Any mesomorph or athlete with muscle mass will most likely come out as overweight.

 

 

I picked that study at random from dozens of results. But it's typical.  The r^2 tends to sit around 75% for men and 80% for women.  It blurs a bit between ethic groups but a skilled medical professional can tell the difference between a muscular person and a fatty person.

 

For the surgery I had, many tests were undertaken - bloods (dozens of vials in total), urine, CT, x-rays, ultrasound, ECGs, physical measurements, blood pressure.  But there was still a BMI threshold as in: "if you can't get your BMI under XX, we won't perform that surgery on you".  That tells me it's a useful screening measure.

 

BTW Sri Lanka does not have a uniform ethnic make up.  Although the study group may have been ethnically uniform.





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  Reply # 1960942 20-Feb-2018 13:19
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MikeAqua:

 

But there was still a BMI threshold as in: "if you can't get your BMI under XX, we won't perform that surgery on you".  That tells me it's a useful screening measure.

 

 

 

 

Problem is you can't tell from BMI what percentage of weight is muscle vs fat. Those with significant muscle will be classified as overweight or even obese despite have excellent cardio fitness and low fat percentage.  Therefore it's hard to know how much sense it makes to say "BMI overweight by 3%" improves health because pretty much anyone who lifts weight at the gym is going to be classified as overweight by BMI or even does decent intense exercise I think... my point is I'm not sure how useful it is in a study like this to use BMI as a measure of health because it really depends who they've included in the study.




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  Reply # 1960957 20-Feb-2018 13:35
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I wouldn't get too wound up about the details of how they measured BMI - it was the least significant thing on the list.  Having hobbies, drinking wine and coffee seem to be much more important.  Perhaps we need more information as to whether sitting on a couch watching TV is a beneficial hobby, the wine needs to be of a certain quality or will something in a cardboard box do, and whether "International Roast" instant coffee as dispensed from office coffee machines would have the desired effect on longevity?

 

 


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  Reply # 1960976 20-Feb-2018 13:56
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sidefx:

 

my point is I'm not sure how useful it is in a study like this to use BMI as a measure of health because it really depends who they've included in the study.

 

 

Back to my original point then.  I don' think it's about health in term of cardiac, diabetes etc.

 

I think it's that being a little overweight gives your body reserves to tap into if you get sick.

 

For that purpose it could be extra fat or muscle.  Your body can use either as fuel if it has to.  BMI generally works for that.





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  Reply # 1960982 20-Feb-2018 14:01
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MikeAqua:

 

BTW Sri Lanka does not have a uniform ethnic make up.  Although the study group may have been ethnically uniform.

 

 

Hmmm, you are right about that: Sinhalese 74.9%, Sri Lankan Tamil 11.2%, Sri Lankan Moors 9.2%, Indian Tamil 4.2%, other 0.5% (2012 est.) quite similar to NZ if you swutcg Subgakese for European, Tamil for Maori etc.

 

But Sinhalese and Tamil are probably genetically similar compared to European/Maori/PI makeup?

 

 

 

 


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  Reply # 1960983 20-Feb-2018 14:05
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MikeAqua:

 

But there was still a BMI threshold as in: "if you can't get your BMI under XX, we won't perform that surgery on you".  That tells me it's a useful screening measure.

 

 

But wouldn't that exclude all those obese All Blacks?

 

https://www.odt.co.nz/news/national/obese-and-all-blacks

 

Presumably these doctors know their stuff but this seems very strange to me. BMI is meaningless if you know fat percentage from better methods.

 

 


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  Reply # 1960990 20-Feb-2018 14:25
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kryptonjohn:

 

MikeAqua:

 

But there was still a BMI threshold as in: "if you can't get your BMI under XX, we won't perform that surgery on you".  That tells me it's a useful screening measure.

 

 

But wouldn't that exclude all those obese All Blacks?

 

https://www.odt.co.nz/news/national/obese-and-all-blacks

 

Presumably these doctors know their stuff but this seems very strange to me. BMI is meaningless if you know fat percentage from better methods.

 

 

Perhaps there is wriggle room for very athletic people. I'm not one of them. 

 

Edit: I should have mentioned the cut off was not 30 (where obese starts) it was higher. 

 

No-one did any measurement or made any estimate of my fat % (I read my file cover to cover) BMI was considered sufficient.

 

And again BMI tells you fat percentage (generally).

 

 





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  Reply # 1962691 23-Feb-2018 09:40
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Fred99:

 

I wouldn't get too wound up about the details of how they measured BMI - it was the least significant thing on the list.  Having hobbies, drinking wine and coffee seem to be much more important.  Perhaps we need more information as to whether sitting on a couch watching TV is a beneficial hobby, the wine needs to be of a certain quality or will something in a cardboard box do, and whether "International Roast" instant coffee as dispensed from office coffee machines would have the desired effect on longevity?

 

 

 

 

 

 

Agree, I just suspect (with very little reason, but then this is the internet :P ) that those who are classified as "overweight" because they have too much muscle are probably pulling up that average (BMI being linked to increased lifespan) but being classed as overweight or obese on the BMI scale due to too much fat is not healthy at all....

 

 

 

As for your other points, my guesses would be:

 

Yeah, they probably mean hobbies that get you outside and\or at least somewhat active and on the food scale I would say it has little do do with the quality or cost but more to do with what crap preservatives, etc they put in it ;-)




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  Reply # 1966831 2-Mar-2018 06:48
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tdgeek:

 

That actually makes a lot of sense. Higher fat probably also means higher muscle mass, better that than frail. 

 

 

Damn and tarnation.  Wishful thinking combined with poor science reporting to make internet news headlines seems to have come unstuck.

 

The suggestion that "overweight" and "obese" might be of benefit seems to have been debunked already:

 

 

Prior studies have demonstrated lower all-cause mortality in individuals who are overweight compared with those with normal body mass index (BMI), but whether this may come at the cost of greater burden of cardiovascular disease (CVD) is unknown.

 

...In this study, obesity was associated with shorter longevity and significantly increased risk of cardiovascular morbidity and mortality compared with normal BMI. Despite similar longevity compared with normal BMI, overweight was associated with significantly increased risk of developing CVD at an earlier age, resulting in a greater proportion of life lived with CVD morbidity.

 

 

Oh well, can remain optimistic on the wine and coffee thing I suppose, until those are both debunked.

 

FWIW my guess (and that's all it is) is that coffee probably makes no difference - beneficial or harm, and alcohol in "moderation" is probably okay or even beneficial for some people, but not for others.


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  Reply # 1966869 2-Mar-2018 08:20
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Fred99:

 

FWIW my guess (and that's all it is) is that coffee probably makes no difference - beneficial or harm, and alcohol in "moderation" is probably okay or even beneficial for some people, but not for others.

 

 

Thank you for that, Dr Humphrey Appleby!

 

 


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  Reply # 1967104 2-Mar-2018 14:52
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Correlation does not equal causation. Perhaps people that are baseline healthier (genetics) are more likely to have hobbies in the first place, drink coffee and wine because it doesn't affect them in a bad way, be more inclined to specifically exercise (assuming they're not just meaning a brisk walk around the block) and eat more food.

 

Personally, I simply live my life as I enjoy rather than worry about any conclusions from such studies.


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  Reply # 1967109 2-Mar-2018 15:02
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Better to have a shortened happy life than a lengthened miserable one!

 

 


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  Reply # 1967217 2-Mar-2018 18:21
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kryptonjohn:

 

Better to have a shortened happy life than a lengthened miserable one!

 

 

Yep. Increasing your lifespan only adds to the end of it anyway. I hoping to avoid having to wear nappies again.




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  Reply # 1967256 2-Mar-2018 19:46
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kryptonjohn:

 

Better to have a shortened happy life than a lengthened miserable one!

 

 

As a meat eater, I use this logic to justify my taste for spring lamb.


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