Thursday, 6 August 2015

Healthy Natural Foods: An Evolutionary Perspective

     Most of us don't think very intently about biology. Physics, sure -- we are constantly and often consciously applying Newton's laws whether we're tossing something in the wastebasket or driving down the highway -- but biology? No. Perhaps this is because Darwinian evolution, the central unifying principle of biology, is so poorly misunderstood by the public (thanks in part to creationists who go out of their way to Teach The Controversy in the form of their own tortured misconceptions), or perhaps it is because we fall into the trap of thinking that it's irrelevant to our daily lives, but in any case, it's unfortunate, because we are biological creatures and just about everything about us is informed by our evolutionary origins.
     In this post, I want to show how an understanding of the broad principles of evolution and ecology can help us avoid being taken in by a particular silly health fad, in the hope that the reader might learn to apply a similar critical informed approach to other fads as they appear.

     So let's consider a fairly common and plausible sounding claim here, one that underlies not just the Paleo Diet but a lot of basic "common-sense" thinking about health and food. The idea is that it's better to have foods that more closely resemble the kind of food we must have eaten in our pre-industrial past, natural raw unprocessed foods, because these are the sorts of foods we evolved to eat. Our bodies simply aren't equipped, so the argument goes, to deal with the incredibly rich diet our industrial age allows us, and all those artificial flavourings and preservatives can't possibly be good for us.
     That sounds eminently reasonable, and indeed it does seem to make solid evolutionary sense. After all, if we hominids have had millions of years to refine our ability to produce just the right enzymes to digest fresh fruit and insect grubs, why mess with a good thing? Why on earth would we expect to be able to digest a chemical invented within our lifetimes?

     Well, it's reasonable as far as it goes, but it's also incomplete. What it overlooks is that evolution doesn't just explain how we got here; it's the single unifying principle to all of biology, and also explains how every other living thing got here, including the ones that we eat.
     See, being eaten is usually how you lose the game of evolution. Every living thing on this planet is descended from an unbroken line of organisms that somehow managed to avoid being consumed until they produced at least one descendant. Every single cell in every body traces itself back through such a line to one common ancestor. Countless siblings have died without issue (often eaten by some other creature), but even they were descendants of unbroken lines of successful ancestors.
     This has been going on for something like three billion years. The occasional link in that chain might have survived just by sheer dumb luck, but the law of averages is against luck when such enormous time scales are involved. Most of your ancestors survived because they had an edge over the things that were trying to eat them, or the things they were trying to eat. Not a big edge, mind you. Just enough of one to survive, just long enough to produce offspring.
     Evolution isn't about perfection, after all. It's all about just good enough, but after three billion years of it, just good enough is pretty amazingly good, which is why we (and all living things) seem to be so exquisitely well-adapted to our environments.
     But we're not. The gazelle is just barely fast enough to escape the cheetah most of the time, and the cheetah is just barely fast enough to catch enough gazelles to make baby cheetahs. Plants (including the ones we eat) have evolved toxins or thorns or other defenses just barely good enough to kill or deter things from eating them enough for some of them to produce baby plants. And we became just barely good enough to survive eating those toxins long enough to produce human babies.

     The point here is that the foods we ate in our ancestral evolutionary environment really, really didn't want to be eaten, and they were trying to kill us, and they often succeeded. We just happen to be really tough, and really clever at figuring out ways to get around their defences so we could eat them without being fatally poisoned or otherwise killed. We discovered that if you heat some things over a fire, they become easier to chew and digest. We discovered that if you plant seeds from mutant not-so-poisonous fruit, you get more mutant not-so-poisonous fruit. We learned out to breed plants and animals that were easy to eat, and make more of them.
     While Nature is not exclusively red in tooth and claw, and there are lots of examples of symbiosis and cooperation (like tasty edible fruit to get animals to plant seeds in fresh manure), there really never was an ideal time when we lived in perfect harmony with Nature and it gave us everything we needed to live long happy lives. Modern agriculture and processed foods are not some perversion of what once was good and pure; they are a continuation of what we have always done, which is trying to make sure we have enough food to make babies.

     I am not saying here that all diets are equally healthy, or that natural foods are bad for you. Some foods are certainly much better for you than others, and there are definitely good reasons to pay attention to what we eat. I'm not a nutritionist or a biologist, and I don't pretend to offer any specific advice as to what you should or shouldn't include in your diet. What I am saying is that just as a solid grasp of the concepts of force and momentum can help you to make better driving decisions, a clear understanding of our evolution and ecology can better equip you to evaluate claims about diet and health.


  1. Hmm. If the venom of a Brown Relcuse “Just Good Enough” to cripple and sometimes kill a mammal many orders of magnitude outside it’s competitive milieu, does that make it overkill for it’s usual prey or competition?

  2. Overkill doesn't mean "way better than needed"; it may be just a tremendously lazy shortcut. The spider's genes really don't care about waste that they don't have to pay for; all they want is to enhance the odds that they'll be copied for generations to come, and if that means killing way more mammal than they need to, with just a little more molecular cunning for a venom it's already using on prey, then it's a deal; over time, fewer big animals eating your absurdly venomous offspring is apparently worth it.

  3. You imbue a spider with foresight and the power to develop what will make his progeny survive. Preposterous! God has ordained the balance that you admire, not dumb luck and the wisdom of the creatures themselves. Your refusal to see God manifest before you in all His works and your smart remarks about how stupid you think the creationists are will haunt you in Eternity. You will deserve God's judgment and your arrogance will sink you deep. Yet there is mercy in Christ. Come to Him!

  4. I did not say creationists were stupid. I said they have a tortured misunderstanding of evolution, one aspect of which you have just handily demonstrated: There is no foresight involved on the part of the spider or anyone else.

    Several years ago, I popped a handful of fresh raspberries into my mouth, not noticing that a bright red ladybug was caught among them until my tongue exploded with the foulest taste I've ever encountered. I spat the mess into the sink, and then saw the bedraggled, juice-sticky ladybug crawl out from the ruins. It had survived, not by foresight, but by the good fortune of an instinct to poop out horrible-tasting chemicals when threatened. And, when I saw its distinctive red-with-black-spots pattern, I determined from that point on to avoid eating anything resembling it.

    But here's the part we don't notice: How many bugs have I eaten that did NOT have this foul taste? Perhaps I've even eaten bright red and black ladybugs that were missing this chemical deterrent. There's really no way to know how many have perished this way. I can tell you this, though: the one I spat out survived, and whether or not it went on to make little ladylarvae of its own, its siblings and cousins who carry the same genes have benefitted from the fact that I'm careful not to eat THEM. And over time, with the delicious bugs being devoured at a higher rate than the unpalatable and conspicuous ladybugs, the nasty tasting ones will tend to become more common in the population.

    There is absolutely no foresight involved, except incidentally insofar as I, a predator, have learned to avoid eating ladybugs. But even that is not necessary to the process. If some mindless predators are genetically predisposed to avoid eating bright red things with black spots, they will waste less time puking up ladybugs and have more time to eat more palatable food, and so they will over time tend to do better.

    I do not think you stupid for not understanding this. Natural selection is one of those brilliantly elegant and subtle theories that takes a great deal of thought and insight to be able to grasp. It is not a simple formula like F=ma, to be instantly and intuitively confirmed by tossing a rock. You need to think through the implications of statistics and probability on scales we humans rarely need to consider, and most people don't really have the time to do this. I myself never really GOT the theory until I was well into my university undergraduate studies.

    But it IS a rational, understandable system which can be understood through the exercise of reason. It demands no leap of faith or unquestioning acceptance. You do not need to believe in it to understand it. I know you do not believe it, and that's fine. But it's very clear that you do not understand it well enough to criticize. That is why I am trying to explain it to you.

    1. Atheism itself is a tremendous leap of faith. It involves believing that the vast majority of people who have ever lived were wrong in thinking there was a God. It teaches one to deny the obvious evidence of a plan in favor of a carefully reasoned proposal that all things could happen by chance. It involves believing in the upward movement of life when all the evidence points to atrophy. It believes that mutations are the movement upward when almost every mutation tends to hinder an animal's progress. Millions of people alive today have come to a personal relationship with Jesus Christ, but the atheist takes a gigantic leap of faith, and believes that they are all misguided or crazy and he alone has the truth. A leap of faith and unquestioning acceptance are exactly what atheism requires. Millions have leaped to Jesus and been caught by the everlasting arms.

    2. The "vast majority of people who ever lived" did not believe in the Abrahamic God, though I suppose I could imagine why you might think so if you don't believe anyone lived before 4004 BC. But even today, when Christianity and Islam have spent the last millenium or so aggressively evangelizing to every corner of the globe, slightly more than half of the world's seven billion people believe in that particular deity. And you have disparaged the religious judgment of Muslims too harshly for me to be persuaded that they should count as support for your position.

      And even if the "vast majority" of people believed in your God, that means very little by itself; the vast majority of people have believed a lot of silly things throughout history, and most of us are STILL wrong about most things. I would caution you against appeals to the majority, in any event; as a matter of fact, the majority of scientists (actual, trained, professionally educated working scientists) that accepts evolution IS vast, and they actually know what they're talking about rather better than you or I do.

      As for your arguments against evolution, please just stop embarrassing yourself. If you're going to disavow reasoned argument as a path to know God, please at least recognize that it IS a path to know Nature, and you are way out of your league here. I'm not asking you to accept evolution, but I really would like it if you could stop pretending you understand it.

  5. I do not understand evolution. It is a leap of faith in the views of scientists who themselves say they do not know everything and who expect to change their views several times in their lifetime. No scientist has ever witnessed the beginning of any species. No one was there when it all came into being. The Christian believes that the God who was there has given an accurate account of what He did. The evolutionary concept of beginnings is based upon faith in a philosophical idea that has sought to arrange scientific data to support its concept. That it is logical is to be expected, given logical men developing it. But there is no proof at all that it actually happened. This is where faith comes in for you It is decidedly more a matter of blind faith than you at present realize. But it may be that at heart you realize that you are mistaken in teaching yourself what you want to believe. Personal accountability to the God who made you is not as easy to shake as some people pretend. Jesus still calls you to Himself.

    1. There are two ways we use "I do not understand", and you are using the rhetorical one, a synonym for "I do not agree", because you immediately proceed to try to explain why evolution is wrong.

      When I say you do not understand evolution, I mean you literally DO NOT GET IT. It is gibberish to you. Sure, you get a couple of the conclusions that all the reasoning leads to, but you simply do not comprehend the reasoning that gets us there. It's as if a long and complex algebraic equation reduces to "x=7", and you just think x=3 because that's what you were told. YOU DO NOT UNDERSTAND THE MATH, so you cannot begin to explain how the equation goes wrong; you just disagree with the conclusion.

      But I DO understand the math, at least enough to see that there are good reasons for believing x=7 and not 3. I get that you think it's 3. I get that you feel you KNOW it's 3. I just don't care what you think it is, because you don't know what you're talking about.

      When you don't understand something, there are two legitimate courses to take. The first is to just acknowledge that you don't know, and defer. I don't know anything about football, so if you tell me this team will win the Superbowl, I won't challenge your opinion; I'll just shrug and say I don't have an opinion because I don't know enough to formulate one. If I trust you at all, I might say, "Well, my friends says this team should win, and he seems to know more about it than I do, so if I had to bet I guess I'd go along with him..."

      The second is to do something about it. Make an honest effort to understand it. Ask intelligent questions, and genuinely try to make sense of the answers. But that requires you to entertain, even just tentatively, the theoretical possibility that it might actually MAKE sense, that there might be some truth to it. And I don't think you're prepared to do that. You just KNOW it's all a load of malarkey, so you cannot make that leap of faith. You have tons and tons of belief, but no faith.

      Whereas I have lots and lots of faith, but no belief.

  6. "Where is the wise man? Where is the scholar? Has not God made foolish the wisdom of the world? For since in the wisdom of God the world through its wisdom did not know him, God was pleased through the foolishness of what was preached to save those who believe." 1 Corinthians 1:20-21

    1. Oh. I see. So you have a book that says God likes foolishness and thinks wisdom is for dummies.

      First, as I keep having to point out, I DO NOT BELIEVE YOUR BOOK. That is, I think it's just a book written by human beings with their own agenda, and Paul had more of an agenda than most.

      Second, even if I DID believe your book was a divine fountain of truth, what reason would I have to believe YOU were reading it correctly? Lots and lots and lots of Christians and Jews and biblical scholars have read it and come to very different conclusions from yours. What makes you think your reading of it is the correct one? What makes you think you are so wise as to be able to apprehend what God REALLY means? Or, more to the point, what makes you think the "wise man" Paul is talking about here isn't YOU?

  7. The agreement among all those who regard the Bible as the Word of God is astonishing. In matters of salvation there is a resounding concurrence. To be sure, there are details not essential to salvation on which there are differences of opinion, but these have provoked more Bible study and more prayer than simple agreement would ever have done. Don't sell yourself short. You are able to understand what the Bible says. The issue is always whether a person believes what it says, and that will be your problem. The issue is much more simple than you suggest. On the issue of salvation through the blood of Jesus Christ, Augustine, Calvin, Luther, Knox, Zwingle, Wesley, Moody, Spurgeon, Billy Graham, Tim Keller, R.C Sproul, and a host of others are in remarkable agreement. The plain things are the main things, and the main things are the plain things. Don't be intimidated by the "experts" who do not believe. They are the "foolish" of whom Paul speaks.

    1. Wow. There's agreement among those who agree. That's... astonishing.

      Except I don't think you really want to bring up that kind of an argument in a comment thread that grew out of your taking exception to my talking about evolution. See, among those who actually understand something about biology, geology, or science generally, the agreement about evolution is pretty darned close to unanimous. I do not exaggerate here. Yes, there's lots and lots of lay people who, for religious reasons or just because they don't really understand the theory well enough to make an informed decision, don't believe that we share ancestors with every living thing on this planet. But among those who've actually studied the theory well enough to GET it, near unanimity. WAY mare unanimous than your interpretation of Biblical scholarship.

      See, whether you want to acknowledge it or not, there ARE a lot of serious scholars who study the Bible with great care and erudition, without actually believing it to be divine. There are also a host of others who revere the text as sacred, but still don't accept your reading of it, even on the "main things" and even after years of careful study. You dismiss them as "foolish", and you claim that they're the ones Paul meant, but that's just, like, your opinion, man.

      Which is really what it comes down to. You have your opinion. Fine. I have mine. I don't care what you believe. I care what I ought to believe. What you need to do, then, is show me why I ought to believe what you believe, instead of just repeating it more and more emphatically.

  8. You are adamant that God must bow to your way of knowing, and He will not do it. He made you, and He will call you to account for what you have done with what He has done. He came Himself to earth because your way of thinking and living would never bring you to Himself. You need to be rescued, and He came as the Savior of the lost. Your presuppositions are wrong---how can careful and profound reasoning produce anything of value?

    1. I am not demanding that God bow to my way of knowing. I am refusing to bow to YOUR way of knowing. You, the fallible anonymous commenter, are not God. Your way of knowing is not God's. Neither is mine, but I at least recognize my potential for error.

      Reason has its limits, but to recognize them you must have made at least a cursory exploration of what it CAN do. You smugly dismiss reason, but you are the poor craftsman who blames the tool he doesn't know how to use.

      You are not helping your cause at all. If your goal is to persuade me to come to Jesus, you have AT BEST left me as indifferent to Christianity as when you started, and that only because I have lots of sensible Christian friends to counteract the unflattering picture of Christian thought you inadvertently paint. If you think that constantly haranguing me is an effective strategy, that I'll finally get so frustrated I'll just convert to get you to stop nagging, well, I think you'll find that I'm pretty patient, but when I lose patience with you, I'll just start ignoring or deleting your comments. I assure you, you cannot win this way.