I think part of the problem is a poorly chosen interval for 'normal' BMI. Here's a study that looked at all cause mortality for BMI ranges within the 'normal' BMI range. Along with the usual suspects they compared BMIs of 18.5-20; 20-22.5; 22.5-25; 25·0–27·5 ;
All cause mortality was
1.13 for 18.5-20 'Normal'
1.00 for 20-22.5 'Normal'
1.00 for 22.5-25 'Normal'
1.07 for 25-27.5
The 'Normal' BMI range 18.5-20 is obviously less healthy than the two BMI ranges of 20-22.5 and 22.5-25. It dragging down the average!
18.5-20 should be redefined to underweight, and 'Normal BMI' should be redefined to be 20-25.
I mean, just take a look at it-- it is more unhealthy to be in the 'Normal' BMI range 18.5-20 than it is to be in the 'Overweight' BMI range 25-27.5
Another problem is that people get frail and lose weight before dying. We should have a good longitudinal study able to measure people’s weight before they get suck
This study actually did try to do that. They selected people who weren't sick at the time of recruitment, and threw out the results of anyone who didn't live at least 5 years after enrolling in the study ('without chronic diseases at recruitment who survived 5 years'). And then looked at the deaths over the next 5-10 years. So this is the odds of someone with a BMI of x dying 10 to 15 years out.
The reason BMI is not an effective measure is because it doesn’t differentiate between lean muscle and body fat. It is effective for sedentary individuals because it cannot account for muscular development. A better measure would be body fat percentage as there are huge differences in health outcomes between somebody with a BMI of 28 and 40% body fat and somebody with a BMI of 28 and 10% body fat. Generally the leaner individual will have substantially better health outcomes. Then the counterfactual becomes bodybuilders who have very high BMI’s, very low body fat, but typically a lot of physical damage and health risks associated with the substances they’ve used to enhance their muscular development.
There unfortunately is no perfect measure for all of society due to all the nuances involved.
I do wonder if some sort of calculation could be developed that combines BMI with sometime like A1C which can differentiate between unhealthy “overweight and obese” BMI’s and healthy ones.
Because of all the confounders and the ethical objections to doing controlled interventional studies, it's extremely difficult to do a methodologically sound study of the effects of alcohol or obesity on health or mortality. To the best of my knowledge, there are still legitimate debates over these issues, and I wouldn't trust a bunch of random doctors to adjudicate them.
For obesity, there is the problem of lean vs. fat mass, but also the fact that in some terminal diseases, weight loss can start years before death. So a small number of people who are normal weight because of an undiagnosed terminal illness from which they will die a few years later can greatly increase the aggregate mortality rate for the normal weight cohort.
There have been a few studies that got around this problem by looking at lifetime maximum weight instead of weight at the beginning of the study, and these have found that mortality increases more consistently with lifetime maximum weight than with weight at study initiation.
Here's one such study, which reanalyzes the Framingham data and finds that, among never-smokers, people whose BMIs have never exceeded 25 have the lowest mortality, and that, among people who were normal-weight at study baseline, those who were formerly obese had a mortality rate more than twice that of people who had never been obese.
Which is to say, having read a fair bit of research on question of weight and health, I think that claims that excess fat mass is actually protective are dubious and based largely on studies with weak methodology.
When you have so many studies showing the benefits, and yet the entire scientific community ignores it, then you must assume that they have a narrative and everything else gets built around it. Anything not matching that heuristic gets summarily discarded.
But I guess it will yet advance, one death at a time.
I will just say, as a parent whose experiences with neuropsychological testing in general and IQ testing in particular have made haruspicy seem like a reasonable alternative, that while I am sure intelligence is heritable, I am not sure that scoring well on IQ tests is measuring the same thing as intelligence, at least not in the current system. I have had students with three thousand dollar evaluations and a measured IQ of 95 who ended up being brilliant (later reflected by SAT and similar scores) and don't tell people this, but I've seen plenty of kids test in the higher ranges and frankly, they are bright and normal, but they're not very interesting.
I'll give you another neuropsychology example. One of my kids was driving a car around the room during a break in testing, and this was written up as
symptomatic of ADHD. Apparently, most other children sit and talk to their mothers. He was talking to me, but it was about the car and the floor. I asked him how the testing was. He said, and I quote, "They asked me a lot of questions, and I told them a lot of answers."
Then he wanted to talk about the car.
I don't dispute the ADHD diagnosis. In our family, we disown our kids if they don't get an ADHD diagnosis by puberty. But this was a perfectly normal exchange, and this was not the only time I questioned the rigidity of the administrators. (And these are highly respected professionals - I wanted my kids to have really good evaluations.)
Waaay back in the early 1970s, Flying magazine, I think, reported on a study comparing non-flyers who learned on simulators, some while drunk, some while sober. The drunks later tested better drunk than sober. (I've forgotten almost everything about it by now.) Some radio station had a call-in to talk with some "expert" who hated drunks, and I remember how angry he was that I would even bring the subject up, how irresponsible I was, and how he absolutely refused to discuss the study itself.
Really? Something I saw in a print magazine 50 years ago? You really expect me to dredge up a link to something from 25 years before the Internet was a public thing?
One reason that doctors might hesitate to recommend moderate drinking to their patients is that a small portion of the population are strongly genetically predisposed to alcoholism. A doctor who blanket suggests moderate drinking to his patients will perhaps see a small positive effect for the large marjority of them, but perhaps a disasterous outcome for a few.
That depends on the potential alcoholic being someone who has never tasted alcohol until advised to do so by his doctor, which seems unlikely although not impossible.
Doctors have authority. If a person of authority recommends consuming alcohol regularly, then many people will start consuming alcohol regularly. One drink is usually not enough to create a problem, but regular drinking certainly is. I'm surprised you need this pointed out David.
I feel confident that it is better for you on average to never drink than it is to start drinking one beer a day, and the doctors are in fact making the right decision for people, based on all the factors rather than just a narrow selection.
My suspicion given the vast literature on the issue and how robust the findings are, is that various health authorities either believe that moderate alcohol consumption is good or at least find it fairly plausible, yet know that if they found strong evidence such as a high quality RCT for such a effect and or started recommending moderate alcohol consumption then the general public would use such advice to rationalize bad behaviour etc. and overall public health would decrease."
Since then I found a recent paper https://jamanetwork.com/journals/jamanetworkopen/article-abstract/2802963 and saw a doctor online use this paper as a justification that no amount of alcohol is good for you, with the implicit message being that any amount of alcohol is bad and so you should stop, but after reading the paper the results are pretty clearly that low volume and medium volume alcohol consumption at least for males, has no statistically significant negative effects, in fact the usual pattern is a non statistically significant benefit. Nevertheless people will continue to listen to the various popular public intellectuals and YouTube talking heads on the matter. As I noted in my original comment interestingly the resveratrol hype seems fake https://www.science.org/content/blog-post/speaking-illusions-sirtuins-and-longevity, and hopefully those who have promoted it (Sinclair) will bear some reputational cost, although probably not.
Another striking example of an official truth was the initial rejection of the Covid lab-leak theory, which was denounced as conspiratorial but has since become the dominant theory.
In this case, the error entrenched in the official truth was (or is being) corrected, which is reassuring.
That was an interesting case because the relevant experts had a conflict of interest, an incentive to lie. For the technical evidence, the people most qualified to comment are virologists. If you are a virologist, you very much don't want other people to believe that the pandemic was due to the sort of work you do. If you are a virologist who gets government grants, you certainly don't want people to believe that the pandemic was due to research in virology funded in part by the government.
There was a news story recently about the recent congressional investigations into the question. Some of the authors of an article attacking the lab leak theory confessed that their conclusion was somewhat biased — but their explanation was that they didn't want to encourage hostility to China and wanted to protect Chinese science. So far as I could see, none of them recognized that they had a self-interest motive, although several, according to the news story, had received millions in grants from the government.
I wonder how many people read my posts days, weeks, or months later. I make corrections in part for them, in part because I may eventually reprocess the material into a book or books.
Is the recent record global temperature streak within expected bounds or should it nudge us closer, however slightly, towards the climate doomism side of the spectrum?
I think part of the problem is a poorly chosen interval for 'normal' BMI. Here's a study that looked at all cause mortality for BMI ranges within the 'normal' BMI range. Along with the usual suspects they compared BMIs of 18.5-20; 20-22.5; 22.5-25; 25·0–27·5 ;
All cause mortality was
1.13 for 18.5-20 'Normal'
1.00 for 20-22.5 'Normal'
1.00 for 22.5-25 'Normal'
1.07 for 25-27.5
The 'Normal' BMI range 18.5-20 is obviously less healthy than the two BMI ranges of 20-22.5 and 22.5-25. It dragging down the average!
18.5-20 should be redefined to underweight, and 'Normal BMI' should be redefined to be 20-25.
I mean, just take a look at it-- it is more unhealthy to be in the 'Normal' BMI range 18.5-20 than it is to be in the 'Overweight' BMI range 25-27.5
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4995441/
Another problem is that people get frail and lose weight before dying. We should have a good longitudinal study able to measure people’s weight before they get suck
This study actually did try to do that. They selected people who weren't sick at the time of recruitment, and threw out the results of anyone who didn't live at least 5 years after enrolling in the study ('without chronic diseases at recruitment who survived 5 years'). And then looked at the deaths over the next 5-10 years. So this is the odds of someone with a BMI of x dying 10 to 15 years out.
The reason BMI is not an effective measure is because it doesn’t differentiate between lean muscle and body fat. It is effective for sedentary individuals because it cannot account for muscular development. A better measure would be body fat percentage as there are huge differences in health outcomes between somebody with a BMI of 28 and 40% body fat and somebody with a BMI of 28 and 10% body fat. Generally the leaner individual will have substantially better health outcomes. Then the counterfactual becomes bodybuilders who have very high BMI’s, very low body fat, but typically a lot of physical damage and health risks associated with the substances they’ve used to enhance their muscular development.
There unfortunately is no perfect measure for all of society due to all the nuances involved.
I do wonder if some sort of calculation could be developed that combines BMI with sometime like A1C which can differentiate between unhealthy “overweight and obese” BMI’s and healthy ones.
Because of all the confounders and the ethical objections to doing controlled interventional studies, it's extremely difficult to do a methodologically sound study of the effects of alcohol or obesity on health or mortality. To the best of my knowledge, there are still legitimate debates over these issues, and I wouldn't trust a bunch of random doctors to adjudicate them.
For obesity, there is the problem of lean vs. fat mass, but also the fact that in some terminal diseases, weight loss can start years before death. So a small number of people who are normal weight because of an undiagnosed terminal illness from which they will die a few years later can greatly increase the aggregate mortality rate for the normal weight cohort.
There have been a few studies that got around this problem by looking at lifetime maximum weight instead of weight at the beginning of the study, and these have found that mortality increases more consistently with lifetime maximum weight than with weight at study initiation.
Here's one such study, which reanalyzes the Framingham data and finds that, among never-smokers, people whose BMIs have never exceeded 25 have the lowest mortality, and that, among people who were normal-weight at study baseline, those who were formerly obese had a mortality rate more than twice that of people who had never been obese.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6324399/
Which is to say, having read a fair bit of research on question of weight and health, I think that claims that excess fat mass is actually protective are dubious and based largely on studies with weak methodology.
One obvious (non-controversial) example is ice cream.
https://www.theatlantic.com/magazine/archive/2023/05/ice-cream-bad-for-you-health-study/673487/
When you have so many studies showing the benefits, and yet the entire scientific community ignores it, then you must assume that they have a narrative and everything else gets built around it. Anything not matching that heuristic gets summarily discarded.
But I guess it will yet advance, one death at a time.
I will just say, as a parent whose experiences with neuropsychological testing in general and IQ testing in particular have made haruspicy seem like a reasonable alternative, that while I am sure intelligence is heritable, I am not sure that scoring well on IQ tests is measuring the same thing as intelligence, at least not in the current system. I have had students with three thousand dollar evaluations and a measured IQ of 95 who ended up being brilliant (later reflected by SAT and similar scores) and don't tell people this, but I've seen plenty of kids test in the higher ranges and frankly, they are bright and normal, but they're not very interesting.
I'll give you another neuropsychology example. One of my kids was driving a car around the room during a break in testing, and this was written up as
symptomatic of ADHD. Apparently, most other children sit and talk to their mothers. He was talking to me, but it was about the car and the floor. I asked him how the testing was. He said, and I quote, "They asked me a lot of questions, and I told them a lot of answers."
Then he wanted to talk about the car.
I don't dispute the ADHD diagnosis. In our family, we disown our kids if they don't get an ADHD diagnosis by puberty. But this was a perfectly normal exchange, and this was not the only time I questioned the rigidity of the administrators. (And these are highly respected professionals - I wanted my kids to have really good evaluations.)
Waaay back in the early 1970s, Flying magazine, I think, reported on a study comparing non-flyers who learned on simulators, some while drunk, some while sober. The drunks later tested better drunk than sober. (I've forgotten almost everything about it by now.) Some radio station had a call-in to talk with some "expert" who hated drunks, and I remember how angry he was that I would even bring the subject up, how irresponsible I was, and how he absolutely refused to discuss the study itself.
Link to study?
Really? Something I saw in a print magazine 50 years ago? You really expect me to dredge up a link to something from 25 years before the Internet was a public thing?
One reason that doctors might hesitate to recommend moderate drinking to their patients is that a small portion of the population are strongly genetically predisposed to alcoholism. A doctor who blanket suggests moderate drinking to his patients will perhaps see a small positive effect for the large marjority of them, but perhaps a disasterous outcome for a few.
That depends on the potential alcoholic being someone who has never tasted alcohol until advised to do so by his doctor, which seems unlikely although not impossible.
Doctors have authority. If a person of authority recommends consuming alcohol regularly, then many people will start consuming alcohol regularly. One drink is usually not enough to create a problem, but regular drinking certainly is. I'm surprised you need this pointed out David.
I feel confident that it is better for you on average to never drink than it is to start drinking one beer a day, and the doctors are in fact making the right decision for people, based on all the factors rather than just a narrow selection.
Kirkegaard has a good write up on some of the evidence around alcohol consumption and the J curve, https://www.emilkirkegaard.com/p/is-some-alcohol-good-for-you , I left a comment you might find interesting, here's a snippet " Interesting enough there was actually a RCT planned https://clinicaltrials.gov/ct2/show/NCT03169530 but It was cancelled https://www.nih.gov/news-events/news-releases/nih-end-funding-moderate-alcohol-cardiovascular-health-trial.
My suspicion given the vast literature on the issue and how robust the findings are, is that various health authorities either believe that moderate alcohol consumption is good or at least find it fairly plausible, yet know that if they found strong evidence such as a high quality RCT for such a effect and or started recommending moderate alcohol consumption then the general public would use such advice to rationalize bad behaviour etc. and overall public health would decrease."
Since then I found a recent paper https://jamanetwork.com/journals/jamanetworkopen/article-abstract/2802963 and saw a doctor online use this paper as a justification that no amount of alcohol is good for you, with the implicit message being that any amount of alcohol is bad and so you should stop, but after reading the paper the results are pretty clearly that low volume and medium volume alcohol consumption at least for males, has no statistically significant negative effects, in fact the usual pattern is a non statistically significant benefit. Nevertheless people will continue to listen to the various popular public intellectuals and YouTube talking heads on the matter. As I noted in my original comment interestingly the resveratrol hype seems fake https://www.science.org/content/blog-post/speaking-illusions-sirtuins-and-longevity, and hopefully those who have promoted it (Sinclair) will bear some reputational cost, although probably not.
Another striking example of an official truth was the initial rejection of the Covid lab-leak theory, which was denounced as conspiratorial but has since become the dominant theory.
In this case, the error entrenched in the official truth was (or is being) corrected, which is reassuring.
That was an interesting case because the relevant experts had a conflict of interest, an incentive to lie. For the technical evidence, the people most qualified to comment are virologists. If you are a virologist, you very much don't want other people to believe that the pandemic was due to the sort of work you do. If you are a virologist who gets government grants, you certainly don't want people to believe that the pandemic was due to research in virology funded in part by the government.
There was a news story recently about the recent congressional investigations into the question. Some of the authors of an article attacking the lab leak theory confessed that their conclusion was somewhat biased — but their explanation was that they didn't want to encourage hostility to China and wanted to protect Chinese science. So far as I could see, none of them recognized that they had a self-interest motive, although several, according to the news story, had received millions in grants from the government.
Small correction about BMI: "... since it is merely weight divided by height", sould be "height squared".
Off hand, I would think it would be cubed, oh the theory that weight is proportional to volume which goes as the third power of the linear dimension.
I guess it's just a simple heuristic that matches the data well enough.
https://medicalsciences.stackexchange.com/questions/30864/why-is-bmi-related-to-the-square-of-height
Thanks. Corrected.
I wonder how many people read my posts days, weeks, or months later. I make corrections in part for them, in part because I may eventually reprocess the material into a book or books.
Doesn't substack offer those insights to the author?
If not, it's disappointing.
Is the recent record global temperature streak within expected bounds or should it nudge us closer, however slightly, towards the climate doomism side of the spectrum?
>Liam Hunter was one of the psychologists...
Looks like that should be Liam *Hudson.*
Thanks. Fixed.
Glad I could help. Unrelatedly, have you considered posting your Soho Forum debate? I'm sure many readers would appreciate it.