Well I didn’t want to research it myself. I thought experts here would be a far quicker and better way to investigate it. And some of the replies were good especially one that pointed out the ratios of small intestine vs body length.
(Italicized text from your quote)
According to this paper, the pH in a chimp’s stomach is 2.0:
According to this book, our pH ranges from 1.5-5.0 which is the same range as a dog’s stomach pH. A rabbit’s is between 1.9-2.2 which I guess means that rabbits eat a ton of meat.
When I look at sources not about promoting vegetarianism, I get a very different story than sites trying to give a blanket pH for “herbivore” and “carnivore”.
The language is loose, but, forgiving that, it’s a valid question. (I mentioned in another thread Stephen Jay Gould’s defense of loose language regarding evolution. He says it’s just fine to say that the Cheetah evolved for running, eyes evolved to see, etc.)
Evolutionary survival penalizes us for drinking cyanide, and rewards us for a healthy diet. Also, quality of life issues reward us for a healthy diet, by letting us live longer and to be fit (or fitter) later into life.
It’s all roughly asking, “Is meat part of a healthy diet?” with an evolutionary approach.
Anyway, the question has certainly been answered: we’ve evolved as omnivores, and some animal protein (and animal fat) is good for us.
(See? Same problem. “Good for us” presumes upon certain non-provable axioms. Still, no one here is confused by the phrase.)
His assertion was correct. No *animal *can digest cellulose. Bacteria can.
*By itself, Trichonympha lacks the ability to produce cellulase; it requires bacterial endosymbiotes to produce the cellulase to digest its food
*
And cows, etc have Trichonympha and it’s bacteria do the digesting.
I pointed this out since someone was gonna post “but cows digest cellulose” but not on their own, they can’t.
Blake was correct. This was just added information.
Hmmm… I guess I made another false assertion: “Even though Blake made a false assertion” - it was my belief that he did. (though it still seems he was wrong about crows being kosher)
Now it seems that the answer to the thread’s title is no, we aren’t “meant” to be herbivores.
The best reasons for this involves the article I linked to:
Only a few parts of this were quoted and at least two parts of it were clearly wrong. (Human stomach acidity and length of small intestine)
So that article isn’t very reliable even though it initially seemed to be to just be made up of facts. Thanks for people’s help.
About B12 - if this means that humans can’t survive purely on plants then that is yet another problem with the Bible (that Adam and Eve were meant to survive on plants). I like to collect problems with the Bible.
I imagine anyone wanting to defend that view could just argue a supernatural explanation, such as that humans lost the ability to synthesise their own B12 when they were in the Ark (or that they never needed it until then)
It is probably worth noting that even in cases vegetarian diet imposed by culture, accidental consumption of animals saves the day.
Mites, beetles, weevils, etc are almost universally present in stored grains and beans; aphids and other insects live on or in fresh vegetables - these animals contribute essential vitamins (including B12) to the diet of strict vegetarians.
I think it’s actually true that the feces of these animals also contain useful nutrients - so even if you’ve picked out the mealworms from your flour, the flour still contains some of the animal-derived nutrients you need.
I wish to clarify some details on the B12 issue.
There are three possible sources of B12 in an animal’s diet: other animals, gut bacteria, and contamination with soil/fecal bacteria. Here is a article from a UK vegetarian organization that discusses how a “sanitized” zoo diet typically results in a B12 deficiency in primates unless attention is paid to B12 content/supplementation (first paragraph of “Food Sources of B12”).
Some advocates of the “we are not omnivores” argument point to cultures like India’s Jains that have been vegetarian or even vegan for generations as proof we don’t need animal-source foods. The problem with that argument is that while historically Jains in India have been healthy, in the places like the UK they often develop B12 deficiency. That has everything to do with sanitation. Jains in India eat produce that is still likely to have contamination with all sorts of things, from dirt (which may contain B12 producing soil bacteria) to things like rodent feces or come from fields fertilized with human feces or contains insects (which contain B12, being animals). In the UK, produce in the grocery store is cleaned to modern standards, which pretty much eliminates such contamination and along with it most of the B12. One of the major medical journals in the UK published a paper on this, in the 1990’s if I recall correctly, but I don’t remember the details. The point being this has been thoroughly researched.
So, during the Bronze Age, given the near-lack of modern understanding of germs and contamination problems, vegetables and fruits may well have been sufficiently dirty to supply B12. Along with things like dysentery and other water and food borne disease.
So you either need some animal-source B12, a modern commercially produced “vegan” B12 supplement, or to live in a culture where hand-washing after crapping or shoveling out a stable is a bit hit-or-miss, there are rats in the grain bins, and you wind up eating the occasional maggot, weevil, or other insect critter in the food supply.
OK, here’s my rebuttal to the linked article** John Clay** keeps bringing up.
Actual behavior is exactly what you should look at when “looking at human dietary practices.” Right away, my alarms bells are going off when someone says observing actual practices isn’t the way to determine actual practices.
Right away, we have a flaw in logical thinking: this guy is trying to divide ALL mammals into EITHER carnivore OR herbivore, treating “omnivore” as either non-existant or some sort of rare exception. By definition, an omnivore is “anatomically and physiologically” adapted to MANY types of food, allowing for different diets. They are not specialized, they are generalists.
The problem with discussing mammalian head size and humans is that humans have a very distorted skull due to our large brains, making comparisons with other mammals questionable. The necessary adaptions for our large brains has affected the rest of our skull anatomy, including our jaws, mouth, and teeth. So I question if this is a good strategy for the argument.
The other thing is that what animals do with their teeth humans do with their tools. This is a universal adaption among hominids, which developed stone blades even before they developed brains of our size. Again, comparing the teeth of an animal adapted to using tools for food processing to the teeth of an animal without that adaption is not a valid comparison. Our lineage has been using knives for several million years, this isn’t a recent innovation.
True.
However, this guy also seems to either ignore or not be aware that there are very few PURE carnivore/herbivore/omnivore mammals. It is common for carnivores to occasionally eat plant material, either as the stomach contents of prey (where it is already partly disgested, making the nutrients more accessible to the carnivore) or outright eating of plant materials (seen in dogs, for example, which are notoriously not too particular about what they eat). Likewise, cattle not only consume a certain amount of insect life (to the point some parasites rely on that trait for part of their life cycle) but have been known to consume small critters as well. Hippos have been observed catching and eating birds on occasion.
Animals don’t know or care about human categories. It is normal behavior to “transgress” the categories, and this possibly supplies certain nutrients not otherwise available.
He then goes on to explain that while bears are mostly behaviorally herbivores, anatomically they’re carnivores. WTF? Doesn’t that invalidate most of his arguments?
Which, in the case of humans, means tool use. That’s how humans make capturing prey “practical and efficient”. Oh, and totally ignores carrion eaters who rely on other animals to make prey capture “practical and efficient”.
So… yes, plant material would seem to be an important part of our diet, given those adaptions. That doesn’t eliminate the possibility of eating meat anymore than the more carnivorous adaptions of dogs or bears eliminate the possibility of eat plant material. Omnivores don’t have to be exactly in the middle of the plant/meat divide, it’s entirely possible to be omnivorous in a 70/30 split of diet materials.
But, hey, IGNORE that exception, right, because they you might have to admit that maybe we do have some omnivore characteristics…
And… so? How is that inconsistent with eating BOTH plant and meat?
A quick google given a value of 1.5 pH for human stomach acid. So he’s wrong.
Again, wrong – a quick google says closer to 20-24 feet. Already debunked.
However, not as pouched or as long as, say, that of a horse. Note he is not given actual values here that can be fact-checked. Also, while human colons due absorb water and electrolytes, and while a few vitamins are produced in it almost no vitamins are absorbed from it – you’d have to eat your own shit to benefit from them. Which, admittedly, some animals like rabbits do, but that’s not a commonly observed behavior in humans and indeed is usually indicative of serve problems in the individual.
Again, nothing you can fact-check, this is yet another assertion we’re supposed to take on faith.
Just ignore the dentition, tool use, and intestinal length because it doesn’t support his argument!
Any further clarification need, John Clay?
Broomstick: thanks for that.
Actually I liked The Simpsons explanation about that: https://www.youtube.com/watch?v=uCG7o5VCX4A
… so, you gonna eat that bit or what ? 
Whenever I hear the argument of being a vegan versus being a meat eater, I always think of my own digestive system.
Barring eating rotten meat, I cannot think of a time when meat has given me grief. However, I can think of many times that fresh vegetable matter has resulted in upset stomach or uncomfortable gas.
And now writing the above, I have to say that certain fish also cause issues at times (I get itchy from crustaceans). So I guess I just shot a hole in my argument.
We are. If you look across the globe, humans eat pretty much anything. It’s only when they make a conscious effort to avoid meat that they are not. But those who choose a more restricted diet are a minority, so if we’re talking abut humans (ie, in general), it’s a perfectly good statement.
I think it’s also true that in a pre-industrial context, it’s pretty damn hard to get all your calories from plant material. if Spurious Vegan Claims Guy thinks tools are unnatural, then farming is too - and then you’re a forager, and you’ll need to eat anything that stays still long enough, or runs away slow enough, etc.
Obligatory mention of David Bowie living on milk, peppers, and cocaine. 
Actually, spotted hyenas are primarily hunters, rather than scavengers, and even brown hyenas will catch rodents and the like. Lycaons are also known as hunting dogs, and are thought to be the most efficient hunters in Africa (in terms of kills per attempt), due to highly organised pack hunting; definitely not exclusively or even primarily scavengers.
A marabout’s a Muslim holy man, but I guess that one was a typo for marabou, which do eat a lot of carrion, but also catch quite a lot of small prey. There really aren’t many large obligate carrion eaters out there.
Sorry, your main post was good, but that’s a bit of a personal bugbear.
It’s almost impossible to get your calories from raw vegetables. You’d have to be eating 70% of your waking day, and your stomach would be distended. Or at least thats what Michael Pollan sez.
In order to survive on a "raw food’ vegan diet you have to eat lots of nuts or smoothies, so you can drink rather than chew. or both.