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palou said: [...]That we in a large part survived from plant matter is quite obvious - our brain can't function properly without a decent intake in sugars. What I was, as a whole, contesting is the implication (of your first comment) that it was somehow not natural for humans to eat meat, that we weren't true omnivores. This remains false. Humans do have the evolutionary tools to consume meat, tools which were, in many contexts, quite necessary. I did not contest that SOME populations had access to a fully sufficient vegan diet. It was however not the case of all human populations, and not at all times possible - making our natural capacity to consume meat quite valuable. |
Ah, interesting. Well, in that case, now that I have a better understanding of what you're getting at, I think we largely agree. Populations were largely plant-based, or not, based on geography and food availability. I've never contested that, it's not like I've claimed that the Inuit weren't on a ketogenic diet! :) In fact, there would be no basis for saying that the the most plant-based human populations were the healthiest if there was no point of comparison.
We are both omnivores, or not omnivores, depending on what that means to you. If you're taking a behavioural view, we're undeniably omnivores. If you're taking a biological view, a non-omnivore argument can be made. Yes we can eat meat, but so can a cow. A cow will get sick over time from eating animal products (and mad cow disease came from some idiot humans not only making cows eat animal products, but turning them into cannibals by making them eat cow by-products). I'd argue the same is true for humans, we can eat animal products but we also can get a lot of disease from doing so. But we can also get a lot of disease from eating refined carbohydrates. So a whole food diet is a must to avoid disease, and a plant-based whole food diet appears best overall at avoiding it.
The are humans herbivores or omnivores is an interesting discussion, because both sides have valid points. From memory:
The arguments in favour of us being omnivores as I understand it are:
- we can eat meat, and it can provide nourishment
- with the exception of elephants (and the arguable exception of humans), most intelligent species on Earth are omnivores
- our digestive tracts are remarkably adaptable to different diets, with dramatic swings in digestive bacteria within days (even hours) of a significant dietary change
The arguments in favour of us being herbivores are mo:
- longer intestines (in relation to our trunk length) compared to most omnivores
- flatter teeth (for chewing and grinding) than omnivores, rather than sharp incisive teeth
- ability to move our lower jaw side to side, like a cow, to further enhance chewing
- ability to see colour (ideal for finding edible fruit and flowers), a trait few carnivores and omnivores have
- small mouths in relation to our head size, unlike most omnivores
- upper and lower teeth that meet, unlike most omnivores
- our saliva contain digestive enzymes tooled for breaking down carbohydrates (predominantly starches)
- we have muscular face muscles for extended chewing, and small throats, the opposite of omnivores on both counts
- we can't taste protein; if a human eats a pure protein isolate powder it's tasteless, but to a dog or a wolf it would have a taste
- omnivores have a mechanism for getting rid of excess cholesterol, which humans don't have
- omnivores can produce vitamin C, whereas humans ate so much fruit in times gone by that we had the gene but it turned itself off at some point
- we flat and blunt nails, as opposed to claws
- our stomach is less acidic than is typical for omnivores, and our colon is pouch-shaped which is typical of herbivores
So, if you were an extraterrestrial analyzing human behaviour, you'd classify us as omnivores. That same extraterrestrial looking at our biology might conclude that we were primarily herbivorous and that we seem to have recently lost our way. Ultimately, I err on the side of herbivorous because the majority of our biology seems to point that way, and the (IMO) smoking gun: if we eat too few fruits and vegetables we're likely to suffer and/or die of scurvy, and if we eat a lot of meat our odds of suffering and dying from heart disease, diabetes, cancer, and neurological diseases is very high.
So I would normally describe us as biological herbivores who have become behavioural omnivores and are a long way from adapting to that. However, I would accept an argument that we're omnivores that lean more towards the herbivorous side of the omnivorous spectrum. That would explain our ability to eat meat, but would also explain why we don't thrive on a high-meat diet, and would definitely explain our inability to consume an all meat diet without somehow supplementing the plant-only nutrients we need (like fibre, vitamin C, etc). We can get every nutrient we need on a whole-food, plant-based diet (yes, even B12), but we can't get every nutrient we need on a whole-food, all-meat diet.
