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View Diary: Paleo Man Debunks the Paleo Diet (95 comments)

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  •  Man has evolved a lot in the last million or so (0+ / 0-)

    years. Especially since the discovery and general usage of fire.

    Agriculture has caused drastic changes in our diets in the last few thousand years, and our species has not had time for evolution to catch up.
    Do you have a source for that claim? Because a massive change in diet would almost necessarily mean a change in genes, if only because some folks wouldn't be able to eat it at all and would die before having kids. Huge changes like that have evolutionary effects virtually every time.

    Here's an article on fire and evolution.

    If debt were a moral issue then, lacking morals, corporations could never be in debt.

    by AoT on Thu May 09, 2013 at 09:55:11 AM PDT

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    •  evolution is not instant (3+ / 0-)
      Recommended by:
      melfunction, ScienceMom, Nattiq

      It can take a long time for adaptation to change to occur, especially if, as in this case, the effects of the change (low carb -> high carb diet) don't have much of an effect until long after the age of reproduction.

      Also, evolution, being based on random mutation, does not always lead to optimal adaptation, and more important; adaptation won't happen to traits that don't impact reproduction. So, while people may be somewhat "adapted" to high carb diets, they may still be prone to diseases that show up later in life (30's onward).

      History repeats itself, first as tragedy, second as farce - Karl Marx

      by quill on Thu May 09, 2013 at 10:48:33 AM PDT

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      •  I didn't say evolution was instant (0+ / 0-)

        And nothing you said addressed my point. Agriculture was a bottleneck, that means it applied evolutionary pressure that weeded certain people based on previously occurring mutations and genetic makeup. If there is a sudden bottleneck then evolution does occur on a very short time scale. Like when we see a response to an especially bad disease pandemic when the survivors are all immune, or mostly immune. There are numerous other examples where evolution can occur relatively quickly.

        What you're giving is a very basic version of evolution that doesn't take into account things like punctuated equilibrium and other more recent discoveries.

        If debt were a moral issue then, lacking morals, corporations could never be in debt.

        by AoT on Thu May 09, 2013 at 10:52:51 AM PDT

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        •  not quite right (2+ / 0-)
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          AoT, TiaRachel

          You are saying that a change in diet created an evolutionary bottleneck that strongly drove adaptation. Evolution happens due to differential reproduction, so you are implying that people with carb adapted gene mutations survived more often to reproductive age and/or reproduced more, and that this was a strong effect.

          I'm saying that most of the negative effects of a high carb diet hit well after reproductive age, meaning that people with adapted genes reproduce at about the same rate as those who aren't adapted. And therefore there was likely only a mild selective pressure to adapt to the new diet, and NOT a punctuated equilibrium type evolutionary event.

          History repeats itself, first as tragedy, second as farce - Karl Marx

          by quill on Thu May 09, 2013 at 11:37:51 AM PDT

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          •  This makes much more sense (1+ / 0-)
            Recommended by:
            quill

            I didn't understand what you were saying there, sorry for the confusion. I would still expect that the changes in living conditions would have had an effect too and I'd be interested to see the research on that. Things like disease on how trash, etc. affected people in general, especially infant mortality.

            Göbekli Tepe interests me enormously and makes me wonder how much of a role settlements played in the creation of agriculture rather than the other way around.

            If debt were a moral issue then, lacking morals, corporations could never be in debt.

            by AoT on Thu May 09, 2013 at 11:49:24 AM PDT

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            •  human evolution is hard to figure out (1+ / 0-)
              Recommended by:
              AoT

              I suppose the benefits of food cultivation, and staying in fixed location communities are inter-related, which is to say it may not be a simple cause-effect relationship.

              Which gets to another point about human evolution: we're not like most other animals in that there are complex feedback loops between culture, and the effects of culture (e.g., changing our environment), on our evolution. For example, one culture may value certain physical traits, for no particular reason, leading to sexual preferences and evolution towards enhancing those traits, which in turn feeds into some other arbitrary preference...

              Similarly, as you say, when we change the environment we may end up selecting for traits that help us survive our chosen changes. However, the strength of selection may not be very strong (see my carb argument), and may be diluted by gene flow (people entering or leaving a population). And finally, the rapid pace of cultural change that our species imposes, may cause rapid shifts in selection pressure that adaptation can't keep up with. The result is a global population that has a huge variety of genetic phenotypes, from physical features to disease resistance to genetically based disease tendencies, and frequently no cut and dried adaptationist explanation for how any of it came to be.

              I'm sorry, what were we talking about??

              History repeats itself, first as tragedy, second as farce - Karl Marx

              by quill on Thu May 09, 2013 at 01:40:47 PM PDT

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              •  We were talking about neat complex things (1+ / 0-)
                Recommended by:
                quill

                The other side of all of this is that a lot of people look at how things are right now and expand that to all of human history in terms of survival rates and other similar things. Which just doesn't work. One of the interesting things about humans is that we rally are heading toward some sort of genetic diversification, either through colonization of other planets and the resulting isolation, or through a population bottleneck. Not 100% guaranteed, but it seems pretty likely. Given the current increase in genetic diversity and interbreeding between different genetic lines, which is really unique in human history, I think there will be some interesting results from that. Though obviously I won't be here to see it.

                If debt were a moral issue then, lacking morals, corporations could never be in debt.

                by AoT on Thu May 09, 2013 at 01:53:18 PM PDT

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                •  I don't think the future is so bright (1+ / 0-)
                  Recommended by:
                  AoT

                  I think that, basically, humans have replaced genetic adaptation and natural selection with cultural adaptation and technology. We don't evolve naturally any more, and thanks to ethical/moral concerns we aren't allowed to evolve un-naturally either, which means we are basically stuck with the current gene pool for the forseeable future.

                  In a few hundred years, climate change will degrade the the Earth past human livability in most parts, and there is a strong likelihood that an energy crash will turn back the clock on technology (sure we know how to build a rocket, but there's no fuel to run it), at which point I think that our goose will be cooked.

                  But, a hell of a lot can happen between now and then, and who knows - we may yet figure out how to pull our asses out of the fire.

                  History repeats itself, first as tragedy, second as farce - Karl Marx

                  by quill on Thu May 09, 2013 at 06:05:42 PM PDT

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