[Ron] Hi Phil, 
[Ron] Thank you for your many kind comments. 

[Phil] Another factor is that we modern humans tend to have a goal of optimizing our diet for reasons like health, performance, longevity and well-being. Nature doesn't "care" about these goals. 
[Ron] On the contrary, I think that nature continues to hone our adaptations to particular environments, leading to improved health, performance, longevity and well-being (except, of course, those who are trimmed from the gene pool). I do agree that survival and procreation advantage is the first, most powerful, and most rapid selection process. I also agree that " Our current rough notions about an evolutionary template are a starting point, not the final answer for everyone." 

RH: It is sufficiently altered that such a shift would not be likely. But how many of us would have expected Icelandic ponies to be able to survive eating fish? 

Fascinating. Thanks for sharing that. It undercuts the vegan argument that eating meat or fish requires lots of adaptation. Do you have a cite? 
[Ron] Unfortunately, no. This is a remnant of a lesson from when I was in grade 4. My teacher taught us that Iceland was settled by Danes and people from Ireland and Scotland sometime in 800s and 900s AD. Horses were an important status symbol in the Danish culture of the time, and were also a part of their religious exercises. The settlers discovered that grazing livestock caused soil erosion and they outlawed further importation of the horses (I'm not sure when this was but my sense is that it was sometime in the 10th Century.) Fish were plentiful in Iceland. In order to reduce the negative impact of the horses on the environment, the Icelandic settlers mixed fish and fish parts into the horses' feed to provide some of their protein from plentiful fish rather than from scarce browse. Then, during a cold spell, there was so little browse that many of the horses were either slaughtered for meat or were fed fish to get them through difficult winters. My teacher blamed the fish diet for their stunted stature and their unusual body shape but she admitted it was conjecture on her part. Because her parents were Icelandic, I took this information as being fairly authoritative. I also thought she was stunningly beautiful and yearned to be older.   

[Phil]By coincidence, I found that there is a connection to Icelandic horses with my native homeland of Vermont: http://www.squidoo.com/what-do-icelandic-horses-eat-fish-
[Ron] I read that site. It doesn't square with what I remember of what we were taught, but that was in about 1956 so my memory might be a little compromised - especially as I was dazed with love for an older woman at the time. :-) 

[Phil] Interesting, that was my hunch when I first learned about Paleo too, but with all the genetic mixing and dietary changes over the last ten thousand or so years, 
[Ron] Yes, especially with the genetic mixing that has taken place in the last century or so, as we learned to travel further and faster.
[Phil] it's even harder to guess which foods one's genes might have become recently more adapted to than it is to figure out what's "Paleo." 
[Ron] And what's Paleo for which population, and what population do most or all of your genes come from. 
[Phil] I have learned that I have a gene for lactase persistence, which does match the pastoral background of my Irish ancestors. 
[Ron] That's interesting. According to the geneticist Stephen Oppenheimer, in his book titled British Origins, the Irish have maintained a _relatively_ homogenous genetic makeup with a significant component of Viking genes. 

[Phil] Despite that, I find that I don't seem to digest pasteurized cow's milk or ghee as well as "Paleo" aka "NeanderThin" foods. Raw sheep's cheese is easier for me to digest than any cow's cheese or cow's-milk-ghee. Pastured butter seems pretty neutral for me at the moment. I haven't noticed much in the way of either plusses or minuses from it. It's interesting that sheep's cheese seems to be easiest for me to digest among dairy products tried so far and sheep are a traditional animal in Ireland, fitting well with my mostly-Irish ancestry. Is there a true link? I don't know.
[Ron] If you ate gluten foods for a long time, it may have predisposed you to developing dairy allergies that you might not otherwise have developed through increasing your production of zonulin. 

RH: In an uncontrolled environment, over sufficient time, those with optimal health will ultimately outstrip less healthy people in survival and reproduction. 

[Phil] That happens in the wild, but it didn't happen in human history. Instead, during the Neolithic Revolution, the sickly city folk out-reproduced, conquered, enslaved and exterminated the healthier remaining hunter gatherers, whose numbers continue to dwindle while the cities continue to grow.
[Ron] I suspect that is a brief anomaly that would be self-correcting over time. I also suspect that a correcting trend has already had a significant impact. The "forbidden fruit" of suitors and damsels from the lower classes frequently mixed their genes with the upper crust. One of my relatives, a McMurdo, was sent to Canada after having gotten a serving girl pregnant. I would not be surprised to learn that a few wives who were bored or just not enchanted by their chosen husbands chose to dally with some of the service people. It may not fit very well with our sense of propriety, but it certainly fits with our status as primates. (Primates are a decidedly randy bunch on both sides of the gender divide. :-)  

I have heard that you have serious disagreements with Tyler Durden, 
[Ron] I haven't heard of him, so it would be difficult to disagree with him. His surname is of particular significance to me, so I'm pretty confident I would have remembered an encounter provided his name was given. 
Nonetheless, I don't usually avoid posting somewhere just because someone disagrees with me. If I did that, I'd have to leave my wife. She hardly ever agrees with me. :-)

Best Wishes, 
Ron