Thanks @prognastat, that's a very useful summary and catches a lot of fallacies that hadn't occurred to me at all.
It seems like it may be time to wrap up because it is clear cobb and I are talking past each other and we're just repeating the same points instead of at least coming up with interesting new arguments for or against to debate.
While I was writing this post it seems cobb came to the same conclusion independently (see post above), so that's good. 1) Cobb, you seem to subscribe the the belief that anything that is unhealthy in excess is obviously unhealthy in any amount at all. I disagree with this point both generally (I've cited examples of other things we eat where both too much or too little is harmful to human health), and specifically with regard to animal derived foods, pointing out both studies that find those who eat a little red meat, or fish, or vegetarians tend to die at lower rates than strict vegans, and anecdotal data that the longest lived populations on earth generally consume some amount of meat and/or animal products. Note that even so, I'm not arguing that a vegan diet cannot be healthy, simply that there is absolutely no evidence that such a diet is automatically healthier than a diet containing moderate amounts of meat.
2) It is my position that figuring out whether eating meat is unnatural, or whether eating meat is unhealthy, is a separate debate from whether eating meat is ethical. I seems to me like you don't treat these as separate these concepts, so when people push back on your view that it is obvious any amount of meat in the diet is unhealthy or it is obvious that human beings are naturally herbivores you interpret that as an attack on your choice not to eat animals for ethical reasons.
Less seriously:
3) I have continued to monitor my chewing since you brought up the idea that humans are side to side chewers and we just don't realize it. So far I really don't notice much of any side to side motion. I've tested while eating a sandwich, fried sweet potatoes, chana masala (essentially chickpeas), and a carrot (obviously not all in one sitting). If you think there are other foods that evoke a stronger side to side chewing response, feel free to suggest some. Or if other people notice horizontal chewing motions, I'm certainly open to the idea that my jaw movements and/or skull shape may be non-representative of humans as a whole.
4) What's ironic about my username containing the word for corn?
I'm going to answer one more point again because it really is at the core of the impasse we've had in this discussion.
Again, why not take it to its logical conclusion that if a culture that eats a lot of meat is like a 2 out of 10 health wise, and a culture that has little is like 7 out of 10, then maybe a culture that had none would be even higher?
This would actually be a very logical thing to do if the only people who had ever lived were those who ate a lot of meat and those who ate a little meat. If I was in charge of trying to come up with the diet that would keep people alive and healthy for as long as possible and someone came to me with that result and nothing else, I'm smack my hand against my forehead and say "By gosh, we aughta have some folks try eating no meat at all right away and see what happens!"
However, we don't only have data from "lots of meat" and "less meat" we also have data from "only fish", "no meat, but still eggs and cheese" and "not meat, no animal products." We have this data both in terms of very large population surveys of individuals and their health outcomes, and also looking at health outcomes across whole cultures who have adopted different diets for reasons ranging from economic to religious to "this is what tastes good to us." And we don't see any positive health consequences, and
may actually see some negative ones when the average person gives up fish, eggs, and/or small amounts of land meat.*
Maybe it'd be more clear if I flipped your previous statement around:
If a culture that eats no meat or animal products is a 7 out of 10 health wise, but cultures that eat some meat or eggs or fish are 9 out of 10 health wise, wouldn't a logical conclusion be that a culture that ate entirely meat would be a 10 out of 10 health wise? If those were the only two data points we had, we'd have to agree that seemed like a logical conclusion. Fortunately, we do have more information that that, so we can conclude that maybe cheeseburgers every single data might not be the healthiest thing for a human being. But my hope is that this counterfactual example illustrates how, when you remove a bunch of the data from a comparison, you can get misleading trends. And that's what you're doing by making statements that only consider that data on high and low meat consumption, without including the data on the health of vegans, vegetarians, and fish eaters.
I hope this helps to explain why people aren't being as convinced by this particular argument as it sounded like you were originally expecting them to be. I know it can be a very frustrating or unsettling feeling when people respond to actions or words in ways that aren't at all consistent with how I had been expecting them to react.
*It is also important in these discussions to distinguish between "what an ideal diet X looks like" and "what people actually do when they adopt diet X." This works both ways. It's likely many people eating a vegan diet aren't eating an ideal one, with possible negative health consequences relative to an ideal vegan diet, and it's likely many people who tell themselves they aren't going to adopt any diet with strict rules, just make healthy eating decisions end up circling back towards a standard american diet (with definite negative health consequences relative to the ideal diet for a human) simply because having to make judgement calls each time you sit down to a meal quickly introduces decision fatigue.
I think that is why many folks who adopt almost any diet (vegan, vegetarian, gluten free, carb free, paleo, keto, what have you) end up feeling a lot healthier. Absolute rules take a lot less mental energy to follow, and at this point most changes from the standard american diet tend to be improvements.