Health risk between vegans, vegetarians, fish eaters, low meat eaters and meat eaters.

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Health risk between vegans, vegetarians, fish eaters, low meat eaters and meat eaters.

Post by rarity » Tue Mar 13, 2018 5:04 am

So I was talking with someone who told me that the health risk was about the same in low meat eaters, fish eaters, vegans, and vegetarians. To justify their claim they sent me this study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4691673/

So I wanted to know from that if it's true and don't know much about how you read those health studies, or just unsure. The HR stands for Hazard Ratio and the lower it is the lower risk, right? That person started an health debate with me even if I'm not much of an expert to try to convince me that eating either low meat, fish, vegetarian or vegan didn't make any significant change in your health or the mortality rate. So I'd like to have some explanation here. As I read it looks like they're right but again I'm not that good at reading those studies. So is it true that on the health side there is no significant difference in mortality?

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Post by mkm » Tue Mar 13, 2018 7:10 am

What's the most surprising for me is that vegans specifically have much higher risk of dying from cerebrovascular disease (strokes(?)) (1.63) and diseases of respiratory system (1.57). Maybe partial answer is in the table 1 of the study, where one may check that Vegetarians were the least likely (excluding regular meat eaters) to take supplements regularly. I want to believe that that's the case and above risks would be mitigated with adequate supplementation of B12 and keeping the omega-3/omega-6 ratio in check.

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Post by brimstoneSalad » Tue Mar 13, 2018 2:25 pm

As mkm said, the supplement issue is big: many of the vegans in this study were deficient, and we know that (mechanistically) that's a risk factor. It should have been accounted for. The fact that mortality rates were similar despite that is impressive alone.

These people are a tiny bit nutty, but this is a pretty good breakdown of the issues:
https://www.crsociety.org/topic/11450-why-dont-uk-vegansvegetarians-live-longer/

The Adventist study wasn't great either, but their vegans were actually supplementing, and there the mortality difference was pretty clear.

Jack Norris also has a brief article on the issue:
http://jacknorrisrd.com/mortality-rates-of-vegetarians-and-vegans/

There just were not enough vegan deaths in the study to achieve statistical significance even if vegan was better. The study should not have attempted to say anything about vegans.

Other likely confounding variables, since they seemed to have been following typically poor diets, are trans fat consumption (which they do not seem to have even assessed). Vegetarians are more likely to eat butter, while vegans of the time the study was going on are likely to have been substituting margarine which is rich in trans fat. Trans fat is now being removed from the food supply.

Population studies are typically terrible, because there are too many variables to account for and rarely do studies do so properly, particularly when they have such small samples.

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Post by carnap » Fri Mar 16, 2018 12:49 am

rarity wrote:
Tue Mar 13, 2018 5:04 am
So is it true that on the health side there is no significant difference in mortality?
The studies comparing vegetarian diets to non-vegetarian diets are all problematic, but is it really surprising that a food source that our ancestors have been consuming for millions of years isn't the kiss of death?

This is why its not a good idea to try to motivate vegetarian, vegan, etc diets on the basis of health....the studies are conflicting and there isn't any mainstream organization out there claiming that vegetarian diets are healthier so people will have no trouble finding contrary information.

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Post by brimstoneSalad » Fri Mar 16, 2018 4:34 am

carnap wrote:
Fri Mar 16, 2018 12:49 am
rarity wrote:
Tue Mar 13, 2018 5:04 am
So is it true that on the health side there is no significant difference in mortality?
The studies comparing vegetarian diets to non-vegetarian diets are all problematic, but is it really surprising that a food source that our ancestors have been consuming for millions of years isn't the kiss of death?
Consuming in much smaller amounts, mostly from insects, along with other classic treats like feces.
We've only had brief excursions into higher meat diets.
Things we evolved tolerances to also only tell us what probably won't be harmful within the typical reproductive lifespan; not in middle age. Humans today live longer than any of our ancestors do or ever did, and that allows a whole host of problems to arise from diet that have never applied much evolutionary pressure to our ancestors.

Appeal to evolution or ancestry are very bad arguments for the healthfulness of anything outside historical consumption patterns and the 40 or so years of useful reproductive lifespan for most members of the species.

This, of course, includes fruit (I've gone into the potential problems with fructose-rich diets before).

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Post by carnap » Fri Mar 16, 2018 1:47 pm

brimstoneSalad wrote:
Fri Mar 16, 2018 4:34 am
Consuming in much smaller amounts, mostly from insects, along with other classic treats like feces.
We've only had brief excursions into higher meat diets.
You seem to be describing the diet of chimpanzees which was likely similar to our very early ancestors but not are more recent ancestors, around 2~3 million years ago our ancestors started to shift towards a diet with more meat. Its hard to know exactly how much, but there is ample evidence of increased hunting.

We also have a good deal of data from observed hunter-gather groups which can give us an idea how people ate before agriculture, average meat intake in these groups is noticeably higher than what is seen in modern western states.

brimstoneSalad wrote:
Fri Mar 16, 2018 4:34 am
Things we evolved tolerances to also only tell us what probably won't be harmful within the typical reproductive lifespan; not in middle age. Humans today live longer than any of our ancestors do or ever did, and that allows a whole host of problems to arise from diet that have never applied much evolutionary pressure to our ancestors.
Life-expectancy is higher in modern populations but that doesn't mean people weren't living to old ages into the past. They were and the way we age hinges on our evolutionary past not current medical technology. For example with excellent medical care chimpanzees still have around half the lifespan as humans. The primary reason life-expectancy is lower in non-modern societies is that they have much higher infant and childhood mortality rates.

So the idea that there would be no evolutionary pressure isn't accurate, in fact, there would be a good deal of pressure because elders are an important aspect of pretty much every human culture and help their offspring reproduce. Why would, for example, menopause exist in humans (a trait almost unique to humans) if human women weren't often living past middle-age? You don't become menopausal until your 50's.
brimstoneSalad wrote:
Fri Mar 16, 2018 4:34 am
Appeal to evolution or ancestry are very bad arguments for the healthfulness of anything outside historical consumption patterns and the 40 or so years of useful reproductive lifespan for most members of the species.
Evolution doesn't optimize so our evolutionary diet doesn't tell us what is necessarily the most "healthy". But that wasn't the point of my comment, the point was that it shouldn't be surprising that meat isn't a great demon in our diet because its something our ancestors have been consuming for millions of years.

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Post by brimstoneSalad » Fri Mar 16, 2018 7:33 pm

carnap wrote:
Fri Mar 16, 2018 1:47 pm
You seem to be describing the diet of chimpanzees which was likely similar to our very early ancestors but not are more recent ancestors, around 2~3 million years ago our ancestors started to shift towards a diet with more meat.
Our most recent ancestors ate a largely starch based diet (as much as I dislike McDougall, that much is true). We've been doing agriculture for a very long time, and even dogs have evolved in accordance with our diets: https://www.sciencenews.org/article/starchy-diet-may-have-transformed-wolves-dogs
You can cherry pick a narrow evolutionary range where meat consumption was highest, but that doesn't make a good argument.

I addressed the same kind of cherry picking in this thread with a mostly fruitarian:
http://philosophicalvegan.com/viewtopic.php?f=7&t=3347
carnap wrote:
Fri Mar 16, 2018 1:47 pm
We also have a good deal of data from observed hunter-gather groups which can give us an idea how people ate before agriculture, average meat intake in these groups is noticeably higher than what is seen in modern western states.
During a narrow span of evolution, and for a few fringe and not particularly long lived groups.
carnap wrote:
Fri Mar 16, 2018 1:47 pm
Life-expectancy is higher in modern populations but that doesn't mean people weren't living to old ages into the past. They were and the way we age hinges on our evolutionary past not current medical technology. For example with excellent medical care chimpanzees still have around half the lifespan as humans. The primary reason life-expectancy is lower in non-modern societies is that they have much higher infant and childhood mortality rates.
It's a common paleo myth that ancient humans lived a long time, and it's also a common retort that the numbers for life expectancy are just suppressed by infant mortality.
We know the adult life expectancy was in the late 30s to early 40s based on skeletal remains which are rarely older than 40.

Some people lived longer, but surviving into old age was uncommon, which perhaps made elders rare and special if you like, but doesn't make for a strong selective pressure. Death by acute infection/sickness or by violence was the overwhelming cause, leaving degenerative diseases a very small ability to exert selective pressure.

Chimpanzees can live into their 70s, but they don't have that excellent of care in zoos; captivity also often results in depression. It's surprising they live as much longer as they currently do in captivity given the circumstances.
Regardless, obviously aging has a lot to do with growth rate, but there's no reason to believe that humans evolved to live longer. Slow maturity in humans more likely has to do with brain development than trying to preserve the species into old age if that's what you're implying.

http://www.sciencemag.org/news/2014/08/why-do-humans-grow-so-slowly-blame-brain

Some modern hunter-gatherer people live a little bit longer than our ancestors once they reach adulthood, but the reasons for that are complex and probably have more to do with changes in cultural practice and access to trade and humanitarian aid.
There's no good reason to believe our ancestors experienced any significant selective pressure against atherosclerosis, particularly since physical activity and low incidence of obesity would have likely delayed lethal incident past the 40s.
carnap wrote:
Fri Mar 16, 2018 1:47 pm
So the idea that there would be no evolutionary pressure isn't accurate, in fact, there would be a good deal of pressure because elders are an important aspect of pretty much every human culture and help their offspring reproduce.
More speculation based on the methuselah-esque mythos of ancient man.

Grandparents are culturally important, but they're perfectly capable of supporting grandchildren in their late 30s when women started having children in their teens.
Elders are not necessarily that old. And again, this is based on modern cultures. Also, these older members aren't always more helpful than they are a hindrance once the children are old enough to look after themselves.
carnap wrote:
Fri Mar 16, 2018 1:47 pm
Why would, for example, menopause exist in humans (a trait almost unique to humans) if human women weren't often living past middle-age? You don't become menopausal until your 50's.
Menstruation is also "almost" unique to humans: https://en.wikipedia.org/wiki/Menstruation_%28mammal%29
Existing only in primates, bats, and the elephant shrew.

Appealing to menopause is a very bad argument that goes against the evidence if you're using it to claim our ancestors regularly lived past 50.
There's no reason to believe that we evolved to experience menopause for some reason, and that it isn't an effect of something else like depleting egg reserves due to the high frequency of ovulation in humans and the long lifespan of modern man.

Other species like elephants don't have menopause, but their estrus cycle is also something like 3-5 times longer than the human menstrual cycle, so in their entire lives they don't pump out as many eggs as a human does before menopause.

We don't need this kind of wild speculation on social evolution to explain something that's very easily explained by basic biology.
carnap wrote:
Fri Mar 16, 2018 1:47 pm
Evolution doesn't optimize so our evolutionary diet doesn't tell us what is necessarily the most "healthy". But that wasn't the point of my comment, the point was that it shouldn't be surprising that meat isn't a great demon in our diet because its something our ancestors have been consuming for millions of years.
It would be a little surprising if it was a major cause of death before 30 or 40. But beyond that it's not really appropriate to even draw the conclusions you're trying to draw from our evolution since there's no reason to believe our ancestors lived long enough or had significant mortality from degenerative diseases of age for it to matter (also, in terms of modern examples the Inuit didn't evolve resistance, which if anyone would you'd expect them to have).
And beyond that, given how older individuals wouldn't be preferable partners for sexual selection, it probably wouldn't even matter if we did live that long because younger males would almost always win anyway given well established weakening after middle age; I don't think the speculative arguments about the importance of elders really make up for that or the lack of evidence for substantial survival into old age of our ancestors.

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Post by carnap » Sat Mar 17, 2018 4:04 am

brimstoneSalad wrote:
Fri Mar 16, 2018 7:33 pm
Our most recent ancestors ate a largely starch based diet (as much as I dislike McDougall, that much is true). We've been doing agriculture for a very long time, and even dogs have evolved in accordance with our diets: https://www.sciencenews.org/article/starchy-diet-may-have-transformed-wolves-dogs
That depends what you mean by "our ancestors", not all people today are the descendants of agricultural people. Agriculture increased the starch content of people's diet and you see the impact of that genetically, people from agricultural populations produce more amylase than those from hunter-gather, tribal, herding, etc groups (they have more copies of the gene). But with plant agriculture came animal agriculture, while many populations likely reduced meat intake when they switched to more agriculture they didn't abandon meat and they also developed new sources of food like dairy. The amount of meat, dairy, etc consumed hinged greatly on the climate of the population so what our "most recent ancestors" did is highly variable and based on your specific heritage.

brimstoneSalad wrote:
Fri Mar 16, 2018 7:33 pm
You can cherry pick a narrow evolutionary range where meat consumption was highest, but that doesn't make a good argument.
There was no cherry picking in my comments, the 2~3 million period is evolutionary significant. 2~3 million years ago is when our genus was created. Homo habilis marks a major evolutionary development and that is when you start to see evidence of hunting. Our ancestors prior to homo habilis are more like other apes.

But again, my point here is that given our 2~3 million history of eating meat it shouldn't be surprising that it isn't some great evil in our diet. In fact that opposite would be surprising, it would be rather surprising that after 2~3 million years of consuming meat we didn't adapt to its consumption.
brimstoneSalad wrote:
Fri Mar 16, 2018 7:33 pm
It's a common paleo myth that ancient humans lived a long time, and it's also a common retort that the numbers for life expectancy are just suppressed by infant mortality.
We know the adult life expectancy was in the late 30s to early 40s based on skeletal remains which are rarely older than 40.
I'm not sure what you mean by "paleo myth" but you seem to be misconstruing life-expectancy. Life-expectancy is the average life-span one is expected to live based on their current age. Life-expectancy actually increases with age, that is, your life-expectancy is lower at birth than it is if you make it to 30. If no age is specified than that is usually understood to mean at birth in which case the primary reason non-modern people have lower life-expectancy is because higher rates of infant and childhood mortality.

I'm not sure what skeletal remains you have in mind because we do have evidence that people in the paleolithic period were living past their 40's with some regularity. Also we can look at observed hunter-gather populations. Estimates of life-expectancy in the paleolithic era are hard to calculate because there aren't that many fossils, but evidence from the upper paleolithic era points to life-expectancy being similar to what it was in Europe until the late 1800's:

http://www.nytimes.com/2013/03/24/magazine/who-lives-longest.html?_r=0

In any case, contrary to your claim the existing fossil evidence shows that it wasn't "uncommon" for people to live past their 40's. It was just less common than it is in modern human societies.
brimstoneSalad wrote:
Fri Mar 16, 2018 7:33 pm
Chimpanzees can live into their 70s, but they don't have that excellent of care in zoos; captivity also often results in depression. It's surprising they live as much longer as they currently do in captivity given the circumstances.
The life-span of a chimpanzee is around 45. Where are you getting 70's from? I'm not aware of any chimpanzee that has lived that long. But an outlier wouldn't define life-span anyways. Human life-span is around 80 but there are examples of people living close to 120 years old.

So human life-span is around double chimpanzees, that wouldn't happen if there was no selection pressures beyond 40.
brimstoneSalad wrote:
Fri Mar 16, 2018 7:33 pm
Grandparents are culturally important, but they're perfectly capable of supporting grandchildren in their late 30s when women started having children in their teens.
The soonest one can start becoming a grandparent is around 32~34 but you seem to be ignoring the fact that it takes 15 years or so to raise a human child. So the soonest one's first grandchildren would become adults is close to 50. That's the soonest assuming ideal conditions. Birth intervals in non-agricultural societies are around every 4 years so a human would have a role as a grandparent well into their 60's.

brimstoneSalad wrote:
Fri Mar 16, 2018 7:33 pm
Appealing to menopause is a very bad argument that goes against the evidence if you're using it to claim our ancestors regularly lived past 50.
There's no reason to believe that we evolved to experience menopause for some reason, and that it isn't an effect of something else like depleting egg reserves due to the high frequency of ovulation in humans and the long lifespan of modern man.
Menopause is observed in hunter-gather societies, not just modern populations. And its actually not just about menopause but rather that unlike other primates humans physical age and their reproductive age are different. That would be a very surprising outcome if there was no selection pressures past your 40's as its a novel trait for a primate. You'd also have to explain why our life-span is magically around 2~4 times other primates.

https://www.news.iastate.edu/news/2013/08/15/primatemenopause
brimstoneSalad wrote:
Fri Mar 16, 2018 7:33 pm
since there's no reason to believe our ancestors lived long enough or had significant mortality from degenerative diseases of age for it to matter (also, in terms of modern examples the Inuit didn't evolve resistance, which if anyone would you'd expect them to have).
There is a reason, we have fossil evidence and we have records from hunter-gather societies. The Inuit have various gene variants that seem to better adapt them to a high meat diet and it wasn't uncommon for the Inuit to live past their 40's. Since so few Inuit are still consuming their traditional diet there is really no way to conduct a modern study on them but what little research was done in the past suggests lower rates (though the evidence is weak). But there is no evidence of higher rates which is what you'd expect if meat was the primary driver of heart-disease in humans.

Some of your comments seem to be based on the "paleo-diet" but that has nothing to do with what I'm discussing, I'm discussing evolutionary biology not fad diets.

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Post by brimstoneSalad » Sat Mar 17, 2018 8:14 pm

carnap wrote:
Sat Mar 17, 2018 4:04 am
That depends what you mean by "our ancestors", not all people today are the descendants of agricultural people.
There may be some very isolated populations where that is true, but for the most part the major populations of the world were not completely isolated, and in terms of human competition agricultural populations destroyed hunter-gatherer populations with technology and warfare.

Unless you're part of one of those rare exceptions, it's not really anything to consider plausible. Even then, it's a stretch given the historically short life expectancy and lack of evolutionary pressure past child bearing age, and the fact that it may not be possible to become legitimately resistant to heart-disease without other serious metabolic and immunological consequences.

Your claim is that meat eating in the human past is evolutionarily relevant and should make us assume it's mostly innocuous and doesn't cause chronic disease, right? That's a bad argument.

The burden of proof for such a claim lies on you, and you must first prove that historically we have lived long enough to make it even possibly a significant pressure, and then you must prove the grandparent hypothesis correct to make it plausible. You can't do either of those things.

Then you'd need to demonstrate that it's even possible (it might be beneficial to have psychic powers too, but that doesn't mean we do) with one example of an animal that is legitimately resistant to cardiovascular disease.
Contrary to myths spread even by vegans [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1312295/] cats and dogs can develop atherosclerosis, it's just not very common likely due to short life spans and the limits of chemistry which won't speed up on their accounts.
There just aren't any long-lived terrestrial carnivorous mammals to look to for study.

Even if the pressure was there (and you haven't demonstrated that it is), there's a good reason to suspect that it's not even possible to really adapt to it to the extent we would regard it as innocuous.
carnap wrote:
Sat Mar 17, 2018 4:04 am
they didn't abandon meat and they also developed new sources of food like dairy.
In much smaller amounts as supplementary nutrition, and again they weren't very long lived on average. Particularly with the rise of agrarian civilization, the grandparent theory becomes even weaker. Old people certainly are not sexually competitive and with the development of technology and writing their folk knowledge became less important too.

Ability to digest dairy is much more variable, since it has only been a major food source in a few regions and contains lactose. There's something you can argue is not very tolerable to certain people even in their 20s and 30s (unless fermented or something), so there is a selective pressure, AND there's an obvious mechanism by which tolerance of lactose can be evolved.

The same is not true of animal products generally which manifest effects too late and may not be possible to evolve any reasonably complete resistance to the effects of.
carnap wrote:
Sat Mar 17, 2018 4:04 am
The amount of meat, dairy, etc consumed hinged greatly on the climate of the population so what our "most recent ancestors" did is highly variable and based on your specific heritage.
That's not relevant to meat in those amounts or any amounts in terms of contribution to chronic illness after typical lifespan and reproductive age.

Diseases of middle and old age are still not evolutionarily relevant, and for many reasons.
You'd have to demonstrate too many things to prove your point; the overwhelming probability is that you fail on one of them and are wrong in your claim.
carnap wrote:
Sat Mar 17, 2018 4:04 am
There was no cherry picking in my comments, the 2~3 million period is evolutionary significant. 2~3 million years ago is when our genus was created.
None of that is necessarily evolutionarily significant to the diet of modern man and what does or does not contribute significantly to disease and death in older age.
carnap wrote:
Sat Mar 17, 2018 4:04 am
But again, my point here is that given our 2~3 million history of eating meat it shouldn't be surprising that it isn't some great evil in our diet.
My argument is that your argument is a bad argument. My argument is not the opposite claim, that evolution suggests it would be surprising if it were not some great evil. Evolution has virtually nothing to say on the matter because the way in which meat likely causes harm is not evolutionarily significant.

Neither you nor McDougall are correct in drawing broad conclusions from evolution about the healthfulness or unhealthfulness of things.

I do not agree with McDougall that the fact that we evolved eating a large amount of starches means they're healthy either.

The burden of proof lies on you and McDougall respectively for your evolutionary claims.

In my view, based on my reading and best guess, the optimal human diet for long-term health and prevention of chronic diseases (including people who "evolved on" starches) probably minimizes starches and sugars to what will provide for immediate energy needs (since carbs are a good energy source, but not good for storage), focusing on low glycemic index plant foods that will digest and release energy slowly and low methionine heme-free plant proteins and polyunsaturated fats for building blocks and long-term energy. Something similar to the "Eco-Atkins" diet, or the recommendations of Fuhrman (who is a little bit crazy, but mostly on the mark with respect to diet). Rich in nuts, beans, tempeh, mushrooms, and vegetables with a modest amount of low-sugar fruit like berries.

It's possible that my guess is wrong, and I'm not going to argue that, but I'm not going to appeal to evolution to try to support my claims since it really has nothing to say about disease prevention after 40. I'm interested in modern mechanistic evidence.

It's entirely possible that meat AND starches (particularly the simple high-GI starches as in rice regardless of how long we've been eating them) are great dietary evils once we pass 40. We should not be surprised about anything like that with respect to our evolution.

If you're arguing otherwise you need to prove that it would have had a strong selective pressure to make it plausible, and as I said it may not even be possible to develop any serious resistance to these things without negatively affecting other attributes of metabolism or immunity.
carnap wrote:
Sat Mar 17, 2018 4:04 am
In fact that opposite would be surprising, it would be rather surprising that after 2~3 million years of consuming meat we didn't adapt to its consumption.
I didn't say we didn't adapt to its consumption, it would be conceivable that we're producing more or less of some digestive enzyme or acid, although there's very little to adapt to so it's very plausible that we didn't really; meat is pretty simple to break down with the same multi-purpose acids and pepsins that we use for anything else.

The Inuit did adapt, but not to meat specifically, rather to burn fat preferentially as an energy source and not go into ketosis with low carbohydrate diets: crucially, that's something that's relevant to young people, not just to diseases of the old. Their adaptations are interesting, but I don't think it's related to this issue.
carnap wrote:
Sat Mar 17, 2018 4:04 am
I'm not sure what you mean by "paleo myth" but you seem to be misconstruing life-expectancy. Life-expectancy is the average life-span one is expected to live based on their current age. Life-expectancy actually increases with age, that is, your life-expectancy is lower at birth than it is if you make it to 30. If no age is specified than that is usually understood to mean at birth in which case the primary reason non-modern people have lower life-expectancy is because higher rates of infant and childhood mortality.
I'm not misconstruing anything. ADULT life expectancy is the life expectancy after people reach adulthood, usually 15, and that is low.

https://en.wikipedia.org/wiki/Life_expectancy#Variation_over_time
Based on Neolithic and Bronze Age data, the total life expectancy at 15 would not exceed 34 years.[14] Based on the data from modern hunter-gatherer populations, it is estimated that at 15, life expectancy was an additional 39 years (total 54), with a 0.60 probability of reaching 15.[15]
34 is a better estimate, because it's based on the environment of the time period including weather patterns, predators, lower technology (even than modern hunter-gatherers) and tribal warfare and rampant murder (including non-ceremonial cannibalism, which was prevalent then and virtually unheard of in modern tribes).
54 is implausibly high, modern tribes are more isolated or civilized by neighboring governments, but even if you split the difference, that's 44. Heart attack risk doesn't start really climbing for men until 45, and for women at 55.
The average first heart attack doesn't occur until the 60's.

Even if it were true that life expectancy were 54, given the low rates of obesity and higher level of physical activity, heart attacks would be infrequent enough to exert virtually no selective pressure before death regardless of diet. And all of this is also contingent on IF the grandparent hypothesis were even correct and selective pressure at that age would be possible because survival of these elders significantly impacts the survival of their grandchildren or great-grandchildren (which I don't think there's credible evidence of). It seems more likely that great-grandparents would be an impediment. And it would require a mechanism to develop resistance to even be possible...
carnap wrote:
Sat Mar 17, 2018 4:04 am
I'm not sure what skeletal remains you have in mind because we do have evidence that people in the paleolithic period were living past their 40's with some regularity.
Are you asking me to prove a negative here?

Can you show evidence of all of these elderly skeletons? AFAIK we only have a few thousand skeletons from the entire period around the world.

I'm not saying they don't exist at all, but that they're comparatively very rare. We would expect a certain distribution around life expectancy for adults, but there are also some potential biases in which skeletons are preserved. Most adult skeletons are relatively young.

We may not have enough data to know for certain, but an adult life expectancy in the 30s or 40s is the most reasonable conclusion.
carnap wrote:
Sat Mar 17, 2018 4:04 am
Also we can look at observed hunter-gather populations.
Also we can look at observed fruit flies and determine that life expectancy is 24 hours. Is is relevant? No.

There are enormous environmental and cultural differences between modern hunter-gatherers and paleolithic man. I explained why I don't think that's useful.

But even if we assumed it was, it's not that high.
Modern hunter-gatherers are not immune to atherosclerosis, people in the developed world just live so long that it's finally become an issue.
carnap wrote:
Sat Mar 17, 2018 4:04 am
The life-span of a chimpanzee is around 45.
Pretty comparable to what we would expect of humans pre-civilization living in similar environments when we are using reasonable estimates. Hmm...
carnap wrote:
Sat Mar 17, 2018 4:04 am
Where are you getting 70's from? I'm not aware of any chimpanzee that has lived that long. But an outlier wouldn't define life-span anyways. Human life-span is around 80 but there are examples of people living close to 120 years old.
You're speculating on how long chimps would live with good conditions; zoos aren't those. They do not have the same lifestyle, social networks, and medical care humans in the developed world have.
Humans taken into captivity in Europe from the "wild" didn't have that great prospects either as far as I know.
carnap wrote:
Sat Mar 17, 2018 4:04 am
So human life-span is around double chimpanzees, that wouldn't happen if there was no selection pressures beyond 40.
I pretty clearly explained how this could happen and how it provides no evidence for selective pressure in later life.
It probably has to do with human brain development and slower maturation and growth. There's no good reason to believe we evolved to be able to be older rather than it being a coincidence. If it were really that useful, we'd probably have better telomere repair and mechanisms to prevent cancer and live into the many hundreds with proper medical care; not only would we live longer, but we wouldn't age as we do.

It's more likely that if we lived that long, the female menstrual cycle would be slower too.
carnap wrote:
Sat Mar 17, 2018 4:04 am
The soonest one can start becoming a grandparent is around 32~34 but you seem to be ignoring the fact that it takes 15 years or so to raise a human child.
More like 27 years old. Menarche is between 12 and 13, probably the same as it was in early hunter-gatherers.

And it does not take 15 years to raise a child; that's an arbitrary number that's often used as a cutoff for adult mortality, but it doesn't mean the children aren't self sufficient before that. Children in tribal societies are much more self sufficient at younger ages.

Here's a baby chopping down a tree branch for you:
https://www.youtube.com/watch?v=KDdXYYLoygM

The idea that a ten year old who grew up in a tribal society seriously needs supervision, and isn't actively working and pulling more than his or her own weight, seems kind of silly. Around 13 is going to be motherhood.
carnap wrote:
Sat Mar 17, 2018 4:04 am
So the soonest one's first grandchildren would become adults is close to 50.
More likely late 30s is the point of diminishing returns for grandparent supervision, and great grandparents at 40 are very likely just dead weight who are another mouth to feed without much contribution since they can't keep up anymore and they're not needed to care for grandchildren. They're also more susceptible to disease, so a large elderly population would create a mobile disease reservoir to promote sickness in the whole tribe.
carnap wrote:
Sat Mar 17, 2018 4:04 am
Birth intervals in non-agricultural societies are around every 4 years so a human would have a role as a grandparent well into their 60's.
Birth intervals are kind of irrelevant, one person can take care of multiple children and there would be a surplus of grandparents and great grandparents if people really lived that long which would be taxing on the population.

You have a lot of wild speculation, but can you prove this is actually beneficial, or is it just an ad hoc hypothesis that backs up your circular logic on menopause?
carnap wrote:
Sat Mar 17, 2018 4:04 am
Menopause is observed in hunter-gather societies, not just modern populations.
Modern hunter-gatherers who live longer.
I'm sure it happened now and then in the paleolithic era, but speculating a biological purpose for it is out there.

Other primates experience it too if they live long enough.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2553520/

We just have very little data on what their lifespans would actually be in a comparative situation to humans, and many also have longer cycles than humans meaning menopause happens later for them.
The bottom line is that menopause happens when you run out of eggs; surplus lifespan is irrelevant, but it's more likely that menopause at 40 proves humans didn't typically live beyond that.

You're trying to use the circular logic of:

'The fact that humans evolved to go through menopause and then live many more decades proves they lived many decades longer than menopause, thus had long lives.'

They didn't evolve that way. You're just begging the question. It's a coincidence of egg depletion and longer life in the modern era.
There's no reason to believe that menopause has some kind of grand evolutionary design because grandparents are so important.
carnap wrote:
Sat Mar 17, 2018 4:04 am
And its actually not just about menopause but rather that unlike other primates humans physical age and their reproductive age are different.
What are you talking about? Reproductive viability is based on the number of eggs and rate of release.
That we happen to outlive that in ideal situations is irrelevant, and probably a coincidence of changes that had to happen for brain development and that only manifested recently in very long lives. There's every reason to believe that humans didn't outlive reproductive viability by long and even then not very often (as in other species in the wild), it does happen in other primates sometimes.

Menopause at 40 is more likely evidence for a life expectancy in the 30s, not evidence for one in the 60s. You're assuming the conclusion you want and forming ad hoc hypotheses to fit it.
carnap wrote:
Sat Mar 17, 2018 4:04 am
That would be a very surprising outcome if there was no selection pressures past your 40's as its a novel trait for a primate.
No, there's no reason to believe any of this is novel.

The only thing that's novel is modern civilization.
carnap wrote:
Sat Mar 17, 2018 4:04 am
You'd also have to explain why our life-span is magically around 2~4 times other primates.
1. It probably isn't that much longer in ideal conditions (captivity is not ideal) as I've said. Comparing the longest lived humans (122) vs. the longest lived chimps (79), it's less than twice the life span (a little over 1.5 times) and humans have a MUCH larger population to get more lucky samples at the extreme end of the curve, captive chimp populations are very small.
2. I did explain that, and it probably has to do with brain maturation delaying development and resulting in slower growth
3. No I don't have to explain it. The default hypothesis is not whatever you pull out of the air. I don't have to explain how the universe got here or else concede defeat to a Biblical Young Earth Creationist either. This is really the crux of the issue: you don't seem to realize that the burden of proof here is on you. I'm only saying that your argument is bad, not arguing the opposite.
carnap wrote:
Sat Mar 17, 2018 4:04 am
There is a reason, we have fossil evidence and we have records from hunter-gather societies.
Please demonstrate the former. I already explained why the latter aren't a great indication.
carnap wrote:
Sat Mar 17, 2018 4:04 am
The Inuit have various gene variants that seem to better adapt them to a high meat diet
They're adapted to a lower carb diet, and to use fats efficiently and to not go into ketosis. That's different. Doesn't mean meat is healthy for them or doesn't cause chronic disease for them, but they perhaps can do well in the prime of life on a high protein and very high fat macro diet where others can not. Doesn't say anything about the effects in older age.
carnap wrote:
Sat Mar 17, 2018 4:04 am
and it wasn't uncommon for the Inuit to live past their 40's. Since so few Inuit are still consuming their traditional diet there is really no way to conduct a modern study on them but what little research was done in the past suggests lower rates (though the evidence is weak). But there is no evidence of higher rates which is what you'd expect if meat was the primary driver of heart-disease in humans.
Weak is an understatement; it was very poor quality evidence. Inuit are an interesting case because much of their fat was marine in origin, which makes it more plausible that their traditional diets aren't as bad, but more recent reviews suggest there's no evidence for it, and in fact that incidence of stroke has been higher so the conclusion that mortality was worse is more plausible.
[...]we find the hypothesis that mortality from IHD is low among the Inuit compared with western populations insufficiently founded. Since
mortality from stroke was higher among the Inuit and Alaska Natives than in the white comparison populations, a general statement that mortality from cardiovascular disease is high among the Inuit seems more warranted than the opposite.
https://www.ncbi.nlm.nih.gov/pubmed/12535749

They also indicate that mortality from heart disease is reducing as the Inuit diet is Westernized, which conflicts with claims about their traditional diet being protective.
The decrease in mortality from IHD in Greenland since 1965 is surprising in view of the rapid westernization of the country during the same period. A similar trend was present among Alaska Natives [13]. If this represents a real decrease in the incidence of IHD and not just a change in diagnostic habits or improved possibilities for treatment, it will be difficult to maintain the importance of the traditional marine diet for a low incidence of atherosclerosis and IHD in these populations
The study suggests that it supports a U shaped relationship between marine fats and mortality. Maybe.
They're definitely not immune to atherosclerosis from their traditional diet, though.

We can talk about the healthfulness of fish -- that's a very interesting discussion -- but it still has nothing to do with evolution, and everything to do with contemporary evidence of the protective effects of DHA.
carnap wrote:
Sat Mar 17, 2018 4:04 am
Some of your comments seem to be based on the "paleo-diet" but that has nothing to do with what I'm discussing, I'm discussing evolutionary biology not fad diets.
You're using the same bad arguments based on a misuse of evolutionary biology. My point is only that it's a bad argument.

If you want to make the argument that meat probably isn't very bad for us, then do it based on high quality contemporary scientific evidence, not speculative appeals to ancestry and ad hoc hypotheses about menopause.

carnap
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Post by carnap » Mon Mar 19, 2018 6:31 am

brimstoneSalad wrote:
Sat Mar 17, 2018 8:14 pm
You're using the same bad arguments based on a misuse of evolutionary biology. My point is only that it's a bad argument.

If you want to make the argument that meat probably isn't very bad for us, then do it based on high quality contemporary scientific evidence, not speculative appeals to ancestry and ad hoc hypotheses about menopause.
Your argument appears to be based on a straw-man, never have I suggested anything about "healthfulness" or "optical diets" or any such nonsense. I made a rather brief comment, namely, that it would be surprising if meat was some "great devil" in our diet considering how long we've been consuming it. The idea that species adapt to their environmental is not a "misuse of evolutionary biology", on the contrary, its precisely what happens.


Beyond that one fundamental flaw in your comments seem to be that you're conflating life-expectancy and life-span and miscontruing life-expectancy. Life-expectancy doesn't tell you much about the distribution of ages so a life-expectancy of, say 50, doesn't mean its rare for people to life past that age. To know that you'd have to look at the actual distribution of ages. Secondly you seem to be conflating life-expectancy and life-span, a species life-span is not greatly impacted by their living conditions. Life-span refers to how the species ages biologically. Chimpanzees age around twice as fast as humans, just as dogs age around 4~5 times faster than humans. By 40 a chimpanzee is elderly where as a human is not. This is key to understanding why menopause in humans is surprising, unlike other primates human women age differently biological and reproduction wise.

A second flaw is that you seem to believe that evolution requires strong selection forces but it doesn't. If there is some gene that protects people from a common disease that strikes when you're 60+ that gene would obviously increase fitness for the individual and the gene would spread in the population. There are a ton of models you can plan with that will show how weak selection forces and dramatically alter a genome.

Lastly you've made a number of bold anthropological claims without evidence while asking me to give detailed evidence, I find that strange. But since each of the claims would require a lengthy discussion I'm not going to further address them.

But these are all tangents in the first place.

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