Every vegan (or vegetarian) everywhere has heard one of these at least once:
"Humans can't survive without meat!"
"We evolved to eat animals!"
"Hunting animals and eating their flesh was what made us human in the first place!"
"Excluding animals from your diet just isn't natural!"
We hear some expert say that humans are so smart because we learned to hunt and eat meat and, as vegans, we collectively cringe. (At the same time, it makes me think that if flesh consumption is vital to brain power, why aren't lions or sharks our intellectual superiors?) We see tribes of chimpanzees in Africa fashioning "spears" to stab other animals to death and then eat them, and another expert compares it to (and holds it up as proof of) our own early history.
I'm personally a pretty huge fan of Science and History in general. In fact, I can sit down and read a book from front to back by Stephen Hawking as easily as most people can read one by Stephen King. Being the analytical thinker that I am, one might see how it could be difficult for me to tackle subjects that interfere with my ethics. Why are there so few naturally vegan sources of B12? How well do vegan sources of Omega-3s actually work?
And, yes, I'm even willing to consider the prospect that humans might have evolved a necessity for consumption of very small quantities or specific kinds of animal nutrients.
I do not think this means that veganism is a waste of time and energy and just going against nature all willy-nilly. There have been several points in history when society has collectively made the decision to stop doing something they had been doing for centuries or even millenia (or start doing something completely different).
There is some archeological evidence that our ancient ancestors ate animals and it's pretty much agreed upon that this happened pretty recently in the evolutionary timeline (which spans hundreds of thousands of years). However, this doesn't necessarily denote a necessity for animal flesh in the human diet, especially when physiological evidence is taken into account.
In times of hardship and scarcity, all animals will eat just about anything to keep from starving to death. Or sometimes they do it just for the hell of it. I actually witnessed an example of this on my front porch this morning when I looked out the window and found a neighborhood cat happily munching away at the sunflower seed bread I had left out for the squirrels. Cats are carnivores, so there's no reason a cat would need to hork down a whole slice of delicious sunflower seed bread.
Imagine you're a human (not hard for most of us) living off of whatever can be scrounged up and a really bad winter hits or even an ice age. Food becomes scarce real quick when everything is frozen. You see a wolf or a tiger happily ripping some smaller animal to shreds and gorging itself on the carcass and you think, "Hey, that animal is surviving by eating that other one! Maybe if I try that I won't have to starve to death!" So you bludgeon a rabbit or something and survive long enough to make little baby cavemen that you can then teach the same thing to and it becomes more of a cultural change than an evolutionary one.
Now I want to talk about B12, the one nutrient that vegans tend to be more deficient in and is harder to find in a naturally vegan format. Let's look back again at how humans used to eat. Before modern concerns about germs and bacteria and before we started trashing our own land, we never really washed our food all that well. It turns out that B12 is found naturally in top soil, especially where other animals have been poopin'. In fact, there is a tribe that has been living in the Himalayas for at least the last 5,000 years on a strictly vegan diet, and it's said that they get their B12 by not being overly concerned with washing their fruits and veggies. Many of them live to be in their 90s, so they're obviously pretty healthy for not consuming any animal products.
Let's examine the logic behind this idea that humans are naturally supposed to eat meat, the non-vegans' favorite argument. We are chided for going against what is natural and seen as plain silly, or worse, anti-human for the digestive decisions we make. But no one ever stops to examine all the other unnatural things that modern advances in technology and understanding have brought us.
Not even 100 years ago a lot of people died from dozens of different diseases and injuries that have now nearly vanished due to vaccination, surgery and education, but you would be hard pressed to find anyone who would suggest that we go back to our previous mortality rate simply because it's "more natural". In the past, birth control was rarely used and was pretty hit-or-miss as to its effectiveness, and it was even illegal in the US at one point, but now 98% of women are using or have used some form of contraception, usually the pill. Try telling a woman she's being "unnatural" and should stop taking her pills and just get pregnant like nature intended and you'll probably get yelled at or even slapped (though if a vegan reacted the same way, we would be labled "crazy" or "extremist"). Less on the medical side (and I know this argument gets brought up a lot, but I'm using it anyway), child labor was pretty common up until the beginning of the last century. If we still had little children doing all our work for us, maybe us adults get get a lot more done. Oh well, too bad societies change, right? (On this last point, I know that child labor hasn't completely vanished and has just disappeared to other parts of the world out of the sensitive sight of Westerners, but the idea I'm trying to portray here is how repugnant we now see it to be, as opposed to our attitudes in the past, which could possibly [and hopefully] be the way animal consumption is seen in our future.)
So, knowing what we know about humans' tendency to eschew nature when it benefits them, it might be easier to understand why vegetarianism and veganism are becoming more and more popular, especially when seen from the aspect of health within a society that's so meat-centric. Cutting animal products from your diet greatly decreases your risk of cancer, heart disease, diabetes, etc and has been shown in multiple studies to increase lifespan. Not only that, but it has the added benefit of being more environmentally friendly and saving other living creatures from needless suffering and death.
My point is, even if veganism is not completely "natural" (which I'm totally not saying that it's not) and you might have to fortify certain foods or look really hard for naturally occurring nutrients, why not go with it now that we have the technology and understanding that it's a better way to live, just like with other medical or social advances?