------Undeniable Evidence (Facts): --------------------------------- -Humans can generally digest diverse amounts of all macronutrients.

True, but trivial. The ability to digest a food, even preference for it, goes no way at all toward showing that it is beneficial, other than avoiding starvation.

-Humans can thrive for the entirety of their life cycle on either a mostly carnivorous diet (eskimos) or a vegetarian diet (induists).

Human beings can survive on a wide variety of diets. Whether or not they thrive on a wide variety of diets remains to be seen.

-Overall, the various forms of nutrition available to human beings haven't impeded the increase of the population and thus reproductive capability in a culturally appreciable manner. (We still have to use contraception regularly, after all, even when sexual disease is excluded.)

Reproductive success is one marker of health, but not the only one and probably not the most important.

-No specific diet has proven the undeniable ability to erase or lower the overall disease rate. -Focusing on one macronutrient above all others leads to nutritional deficiencies. -Demonizing one macronutrient above all others leads, again, to tricky-to-circumvent deficiencies.

Not true. Low-carb diets, for example, can prevent or treat Type 2 diabetes in many people. Also, it's not self-evident that focusing on or demonizing one macronutrient, in and of itself, leads to deficiencies. "Focus" and "demonize" aren't even objective terms. They mean different things to different people.

Finally, if we follow your argument to its logical conclusion, we can't recommend any specific diet, including Paleo, because there are populations who survive on diets consisting mostly of processed foods. So, we're not really left with "common sense" Paleo, we're left with nothing at all.

There are damn few things about which we can draw meaningful conclusions based on nothing more than logic and that which is "self-evident". Diet isn't one of them. We need science for that.

I just realized none of us are really answering the vegan vs. paleo bit of this. There is no historical precedent for any culture surviving and thriving on a vegan diet, no matter how many whole foods were eaten. There may not have been what we would normally think of as meat, but there were always at least grubs, insects, vermin, or shellfish in the diet. Many have survived with very little in the way of animal nutrients, but none have shunned it entirely, so I'm confused about how you keep ending up in the middle as the end product of your thought experiment, thinking either could be equally plausible.

Modern veganism, is in my opinion essentially the fallout of the Edenic cults that have come and gone over the last 3-4 centuries (perhaps there were some before that, but those are the ones I've read about). We can't eat our way back into the garden of Eden, the whole "tree of knowledge" stuff was all an allegory to explain our evolution from large gut, small brain primates to large brain, small gut primates as we learned to use tools and get at bone marrow left behind by the kills of other predators. So perhaps it was less fruit, and more osso bucco that should have gotten Eve into hot water with the big imaginary man in the sky. The main moral of the story is, we can never go back, whether we believe in evolution or Genesis to the word, but that part seems to be largely lost on devout vegans.

You'll see a lot of the "just eat real food" attitude around here. And to answer your question: yes, it does boil down to that in healthy individuals.

Adjustments may be required on an individual basis to both address genetic predispositions (celiacs, for example) and to heal disorders (leaky gut, for example.)

We do it because we don't have all the answers, and because it is fun. Nutritional science is in its absolute infancy, studying evolutionary nutrition is only a small subset of what is being discussed. 16,000+ questions and still going with no end in sight, is a good start. You've read hundreds of articles, as have I, and that has only stoked my desire to learn more. There is a natural mellowing of dogma that happens with increased research, and that might feel like it all boils down to just eat real food. In a perfect world with only naturally occurring foodstuffs this could be true.

However, we have a lot of ill people who have been sufficiently damaged by the industrial food complex and chemical-filled food like substances, not to mention pharmaceuticals or bacterial, fungal, or viral infections who are going to need to find a specific therapeutic diet that works for them to return to a normal enough existence where they can just eat real food.

The changes we've made to the collective human and animal microbiomes via antibiotics, cleaning chemicals, and cesarean birth makes us very different beings than even our parents and grandparents were. Just one example, if someone is unlucky enough to have wiped out their supply of oxalobacter formigenes because they were given antibiotics for repeat ear infections as a child they aren't going be able to break down calcium oxalate, and telling them to just go ahead and eat leafy greens because they are whole foods could get them into trouble with kidney stones.

I think when applying at least a few brain cells to this debate people can tell the difference between the healing diets and the healthy "cruising altitude" ones. Same thing with crazy fringe notions versus actually science. I agree with much of what you have written in regards to healthy people with a healthy digestive tract, but me thinks you are perhaps overestimating your own knowledge and underestimating that of the people who enjoy discussing and researching this stuff.

So, what I've run into over and over again is vegan=politics, paleo=(more often) diet. Very few paleo-centric types argue over whether or not cured leather shoes are paleo, every (in my n=1 world) vegan condemns me for my meat-byproduct footwear.

I've actually had a vegan file an HR complaint against me at work because I brought a (pre-paleo days) Philly Cheesesteak sandwich into the building and it was offensive to his "meat is murder" stance. It went nowhere, thankfully. But that has thoroughly placed veganism in my world view as an extremist religion.

In order to maintain health and optimal function, the body requires a specific amount of macronutrients and micronutrients. Anything outside this specificity threshold is addressed by homeostatic mechanisms, e.g. an excess of calories becomes transformed into adipose tissue. As another example, the detoxification of a substance may place other housekeeping processes on hold and increase utilisation rate of vital micronutrients.

Thus, whilst we have the ability to digest a diverse amount of foods, they each potentially take a toll on our system.

Macro/micronutrients act as energy and structural substrates, and as essential components in catalysis reactions. Importantly, they also act as ligands for many receptors that have downstream communication with the genome.

The genome, which has evolved according to long term environmental exposures, and - in certain genes - may be significantly different amongst individuals, who may respond differently to the same food type. This is the principle of nutrigenomics.

The genome, having developed a mechanism for rapid, short-term adaptation in anticipation of a particular environment may also choose to activate or deactivate specific gene expression pathways. This is the principle of epigenetics.

Given that our primary interface to the environment - the gastrointestinal tract - is colonised by bacteria, it's reasonable to state that our environment is perceived through the prism of our bacterial populations.

It has been recently established that the collective bacterial species that inhabit the gut can be classified according to three types (enterotypes) based on the predominating species. Each enterotype has a different effect on metabolism, particularly in macronutrient conversion (e.g. fibre into short chain fatty acids). Depending on ones enterotype one may be more suited to a vegan rather than an omni diet.

The modern bacterial genome, which is subject to rapid evolution is very likely to be quite different to the paleo bacterial genome.

In summary we have genetics, epigenetics and enterogenetics all playing significant roles in shaping out response to diet. Couple these factors with changes due to ageing, which impacts gene expression further and the relationship becomes more complex.

Therefore to say that "lack of processed foods in the diet coupled with appropriate calorie consumption and expenditure in relation to personal metabolic rate plausibly minimize the rates of obesity and affluence diseases, as long as varied dietary habits are maintained", is risking ineptness. Specifically, it is not sufficient to state "varied dietary habits".

-Humans can generally digest diverse amounts of all macronutrients.amounts of all macronutrients.

Not if you have any sort of digestive issues. A lot of people have digestive issues. Carbohydrates are by far the MOST DIFFICULT macronutrient to digest. What is a vegetarian diet rich in? Carbs.

Humans can survive very easily on most foods.

Thriving into old age and keeping the effects of degeneration to a minimum is the holy grail of Nutritional Genomics..

This in and of itself goes far beyond the Paleo template.Which truly is a fad diet based on a lot of assumptions.