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Paleo, the pace of evolution, and chronic stress

November 21st, 2011

My Jockology column in today’s Globe and Mail takes a look at the paleo diet — or rather, the paleo “lifestyle.” The column is actually in the form of an infographic in the paper, beautifully illustrated as “cave art” by Trish McAlaster. Unfortunately, the online version so far just lifts the text, without any of the data and graphics that accompany it. Nonetheless, it’s hopefully worth a read!

As a teaser, here’s an excerpt from a section on how the pace of evolution has changed over the past few thousand years, and what that means for the quest for the perfect “ancestral” diet:

The paleo diet depends on the assumption that our genes haven’t had time to adapt to the “modern” diet. Since evolution depends on random mutations, larger populations evolve more quickly because there’s a greater chance that a particularly favourable mutation will occur. As a result, our genome is now changing roughly 100 times faster than it was during the Paleolithic era, meaning that we have had time to at least partly adapt to an agricultural diet.

The classic example: the ability to digest milk, which developed only in populations that domesticated dairy animals. More than 90 per cent of Swedes, for example, carry this mutation. Finnish reindeer herders, in contrast, acquired genes that allow them to digest meat more efficiently, while other populations can better digest alcohol or grains. The “ideal” ancestral diet is most likely different for everyone. [READ THE WHOLE ARTICLE]

And, as another teaser, here’s a section of Trish’s infographic illustrating the difference between the acute stress of the paleo lifestyle compared to the chronic stress of modern life:

  1. November 21st, 2011 at 21:13 | #1

    “meaning that we have had time to at least partly adapt to an agricultural diet.”

    This also assumes that the “agricultural diet” has not changed much since inception, allowing for adaptation.

    But, this is not the case. The western diet and food supply has probably changed more in the last 100 years than the whole previous 10,000 years of agriculture.

    Examples:
    Massive increase in PUFA consumption
    Massive increase in sugar (fructose) consumption
    Massive increase in gluten content of cultivated wheat

  2. alex
    November 21st, 2011 at 21:19 | #2

    @David: Yes, I would certainly agree that the focus should be on emulating a pre-industrial diet (a la Michael Pollan) rather than a pre-agricultural diet (a la paleo).

  3. November 22nd, 2011 at 00:19 | #3

    Pedro is Portuguese, not Swedish.

  4. alex
    November 22nd, 2011 at 03:23 | #4

    @Andre: Yes, that should have read “a researcher based in Sweden” not “a Swedish researcher.” My apologies for the error.

  5. Bman
    November 22nd, 2011 at 05:13 | #5

    From the Globe & Mail article:
    1. there are outlier researchers who believe in a lot of vitamin D, but most feel that FDA recommendations are adequate, which do not really require much sun exposure at all (plenty in things like milk). Besides, how do we know that UV radiation was not a major cause of paleo-man having a life-expectancy of 30 years?
    2. go to bed when it is dark and get up when it is light? Up in Canada you guys are going to have awfully short days in the winter. And did paleo-man never stay up past dark?
    3. Can’t argue with that one.
    4. Paleo-man had chronic stress galore. First, the lack of understanding of the world around him would have been extremely stressful, but more importantly, fearing for your life every night, all night, would probably be defined as chronic stress.
    5. There is a far wider range of beliefs of how much paleo-man “exercised”. Many believe that most of the hunting was done by a small percentage of a family-group in many areas of earth (though I guess not true everywhere). Also, not sure how having hard training days followed by early training days really follows anything paleo at all. Having a controlling plan like that seems rather anti-paleo.
    6. The food part is my favorite. There are no foods present today that were around 10,000 years ago… or at least no plant foods that we eat I should say. Human agriculture has affected all of the related wild species as well. Paleo food doesn’t exist, so why try to go there. Maybe it is healthy for one to eat less processed foods if you do not workout heavily, but why kid yourself?

    This whole idea of finding what is natural, what we evolved for, is incredibly humorous.

    First off, if you are reading this you have so much technology that you are so incredibly removed from a paleo-lifestyle it is ridiculous. If you use electricity, use plumbing, use a car, walk on concrete, live in a city at all or even interact with numbers of people larger than a few tens, then your body is so far removed from paleo-life anything else is just a silly gesture.

    Secondly, people always seem to think that evolution is about finding the best solution when it certainly is not. Genes are not selected for the best option, they are selected for good enough. That is what evolution is about. And good enough likely is not close to the best, so why be obsessed with it?

    Caveman lived to 25-30. Modern (Canadian) man lives to over 81.

  6. November 22nd, 2011 at 10:24 | #6

    @Bman
    You go on to make half a dozen points on how it can’t be compared today and how there’s no way to emulate the diet/lifestyle.
    Then you make the most fallacious argument of all: life expectancy. Because medicine and technology has no influence here at all, right? It’s not like it allows people with multi-organ failures to survive, or protects people from viral/bacterial diseases that kept people from reaching ripe ages like 30 a hundred years ago, or allows people with high cholesterol/hypertension/diabetes to keep living functional lives because of that daily pill. Right?

    People already in the agricultural age still had crappy life expectancy before technology and medicine brought us where we are today. Don’t use arguments to support your view that can also be used to destroy your own had you forgot bias.

  7. Chris
    November 22nd, 2011 at 13:11 | #7

    +1 @Andre re life expectancy.
    Also, since when is wild venison not paleo? Or grass-fed buffalo? I could go on…

    Alex, to evolve we need to be able to adapt, which implies that a dietary stress is hormetic. Antioxidants and the examples you give re: Swedes lactase and Finnish herders are examples.

    Grains aren’t hormetic, just like lead paint isn’t hormetic.

  8. alex
    November 22nd, 2011 at 13:35 | #8

    @Chris: “Grains aren’t hormetic, just like lead paint isn’t hormetic.”

    Why not?

  9. Glenn
    November 22nd, 2011 at 19:52 | #9

    Until about 50 years ago almost all the dairy consumed was unpasteurized and the majority of it fermented or otherwise in the form of cheese – even in Sweden!

  10. Bman
    November 22nd, 2011 at 20:32 | #10

    @André: First, modern medicine is certainly not a paleo-lifestyle. Second, food now is PROCESSED with vitamin and nutrient additives making it so we don’t die of malnutrition. As well, the food we grow with modern fertilizers has far, far more nutritive value. Those are both modern, and are the main two reasons we live way, way longer. So do other modern inventions, such as having a clean water source. And people surviving multi-organ failures adds very little to the life-expectancy.

    It’s not complicated: we live way longer in modern times, ergo modern life makes us live longer. It is not even an argument – it is by definition.

    @alex – grains are not hormetic because they are grown with modern fertilizers, usually with modern pesticides, and have been genetically changed (technically engineered or done by human selection) to be very different than they were even 100 years ago.

    I’m not even going to get into how selfish it is to want to go back to paleo methods b/c of how little food is grown per unit area w/o using modern growing methods. Given how poor and desperate for food a large majority of the over-populated earth is, I think it is just completely irresponsible.

  11. patrickg
    November 28th, 2011 at 20:57 | #11

    @André
    People already in the agricultural age still had crappy life expectancy before technology and medicine brought us where we are today.

    Actually, this is incorrect to the best of our knowledge. The most significant impact on mortality was nutrition, followed by sanitation. This is, of course, far later than paleo, but rather up to the 17th century. Technology and medicine didn’t have a lot to do with it.

  12. December 1st, 2011 at 12:40 | #12

    Unless you have sources that would be much more trustworthy than the sources used for this: http://en.wikipedia.org/wiki/Life_expectancy#Life_expectancy_variation_over_time , I have no idea what “best of our knowledge” means.

    And in that case, you’re just wrong. From the early 20th century up until now, life expectancy as ‘only’ more than doubled. That’s technology and medicine for you.

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