The OLDER you are, the more critical a PALEO diet is!
[updated: added link to podcast]
tl;dr - over 30? consider a Paleo diet. over 50? do it now!
I just listened to the best podcast ever last week. I'm still thinking about the insane information density here. It's a brief listen - I think just right around 40 minutes - but if you read between the lines (listen between the words?), there's so much packed into here that it could easily turn into a multi-hour lecture.
I have been under the assumption that the most important time to feed folks a paleo diet was as soon as possible - you know set them up well for life. That's what I did. Our kids have been paleo from day 1. Now that's not bad, and I'm not going to start feeding my kids any grains. But it seems that kids are more able to handle a shitty diet and as you age it more critical to get the diet dialed in.
Over the last decade+ of my involvement in the paleosphere, there has been a constant argument between the orthodox paleos and the NPR-smart (IYI) academic evolutionary biologists about the validity of the basic premise of choosing a paleo diet.
The orthodox argument goes like this: Johnny Caveman only ate meat and whatever fruits and berries he could scrape together, maybe some starches. No grain, no sugar. Our lineage evolved for 99+% of the time under this dietary milieu so we have become adapted to eat this way. Grains and other agriculture products are too novel to our heritage and we have not adapted to eat that way.
On the surface, that makes sense. And if you walk around the Ancestral Health Symposium, that's pretty much what you hear. There will be angels-on-the-head-of-a-pin argument about what fruits and what starches, and if it's fatty meat or lean meat. And then what about sodium? and on and on.
The evolutionary biologists rebut with an argument like this: You dummies, you don't understand science. Evolution can work faster than that, and all it takes in one gene to turn on and you can eat all the grains you want (plus my funding comes from the USDA, so you should eat those grains!). Just look at the lactose-tolerance gene. It only took a few generations for Europeans to be able to tolerate cow and goat milk, so that's perfect evidence that you can eat anything.
Of course, the real answer is somewhere in between. But why it is that way and the implications of that are far more interesting than just saying eat in moderation.
One of my favorite books was Moneyball (anytime the math nerd is the hero, it's a good book) - I didn't see the movie, but if it was as true to the book as The Big Short was, it probably was good. The premise of Moneyball was that there was an undervalued statistic of a baseball player that could be exploited to get someone cheaply. That statistic was the percentage of times they get on first base from their at-bats.
At the time, most people were looking at runs scored, or hits, or something more direct. But the novel logic the protagonist discovered was that if you never get to first you have no hope of getting a run, and if you get to first, your probability of getting a run is infinitely higher than if you never got to first. That is, any strategy to get on first regardless of getting a hit (drawing walks, hit-by-pitches) is a key step in getting a run scored later. If you can find a player who gets on first all the time but has fewer hits (the high-valued metric) then you found someone who will give you a scoring advantage at a much smaller cost.
In a Darwinian evolutionary perspective, reproducing is the most important factor in propagating your genes. If you can't survive to reproduce, you're dead to Darwin. Darwin doesn't care how healthy you are in old age (scoring a run), all that matters is you have demon hell spawn to carry on your genes (getting on first).
Let's say there's a shock to a biological system (e.g., shifting from hunter-gathers to agriculturalists). Immediately there's intense survival pressure for creating new children. This is where the evolutionary biologists have the story correct - we (as a species) are surprisingly quick to change our genetics and epigenetics to survive in a novel situation. A few papers I found suggest that it takes somewhere around 30 generations to fully adapt to a new stressor. So, that's only like 600 years or so, and agriculture is about 10,000-20,000 years old or so.
Ah, so you just proved your thesis wrong! I can go eat donuts and don't have to stick with the paleo diet, ha!
Not so fast - here's where it gets interesting (and I start to put in some of my math on top of what Dr. Rose says in the podcast).
Having children is critical to passing on your genes. But a second order effect is having your children thrive so that they can beat out the other children. How do children thrive? By having their parents be healthy enough to support them as they grow. You gotta get on first, but unless someone after you drives you home, you won't score.
Darwin doesn't care as much about you after you have kids, but if your kids do a little better than your neighbor's kids because you can help them thrive, there is some evolutionary pressure for health post-reproductive adults.
So if it takes 30-ish generations for the kids to adapts, a second-order effect would be something on the order of 30^2 or 1000-ish generations to adapt. Pushing us up to something like 20,000 years for parent-age folks to adapt to the novel diet.
What does that mean? Modern kids probably have the genes to handle an agricultural diet (provided they come from a agricultural heritage - e.g., European and Mid-east, not Native American) because Darwin can move fast and make kids survive. But those genes that get turned on aren't the same genes that make them thrive in old-age, they're the genes that get them to live. There are genes for everything. So initially, there's immense pressure for evolution to figure out which genes are needed to get folks to reproduce. Then after that there's less pressure for evolution to figure out which genes are needed to thrive past reproductive age. So the thrive-after-children genes are discovered much more slowly than the make-more-kids genes.
Modern parents probably have adapted some second-order genes that mean they can probably handle some agricultural food. But older parents are aging out of that right now. That is, you are losing your adaptation to the agricultural food because you are getting old enough that Darwin hasn't had much of a hand in your evolution.
Said differently: Kids today can probably safely eat what kids ate 1,000 years ago. (Parent-age) adults today can probably safely eat what (Parent-age) adults ate 20,000 years ago.
Taking the theory one step farther, grandparents would feel a third-order effect from Darwin. Having healthy thriving grandparents will give their kids a slight evolutionary advantage which will give their kids a slight evolutionary advantage. So (grandparent-age) adults today can probably safely eat what (grandparent-age) adults ate a half a million years ago.
What does that mean to you? Kids - go ahead and eat some agriculture products (though remember, modern wheat is only 40 years old). Parents - start thinking about shifting to a more hunter-gatherer appropriate diet, you're aging out of your ability to adapt to agriculture. Grandparents - throw away the grains! Eat meat, eat whole animal. Get the bone marrow, the offal. Your ability to gracefully age without the wheels falling of is depending on it!
And if you're (or your kids are) eating from our industrial food supply, that's only 2-3 generations old. So, no you haven't adapted to that and it's killing you.
For the orthodox paleos - you don't need to go all insane and make sure your kids have the perfect diet. Relax a little.
For the non-believer evolutionary biologists - the evolutionary story is more complicated, and you should probably start eating more paleo.