How many resources are used to grow, harvest, process and transport an equal energy equivalent amount of veggies compared to meat. A cow does all the veggie processing for you!

An old graph from 2002 shows veggies and fruit are pretty much on par with meat and seafood:

https://learn.uvm.edu/foodsystemsblog/2014/07/10/meat-vs-veg-an-energy-perspective/

No, it wouldn't be worth it. It's unnatural for humans (omnivores) not to eat meat of any kind. Vegans and vegetarians could not live their lifestyle outside of the modern world where they have access to supplements/vitamins, medicine and to a wide variety of foods.

 It *was* difficult to compare omnivorous vs. plant-based societies (there are few, if any, true meat-based societies, scurvy being what it is).  It isn't so much now, thanks to the Adventist study (and, now the Adventist 2 study).  These people belief as an article of their faith that it's important for them to take care of their body, so as to honour the fact that they believe they're made in God's image.  This study is looking at 96K participants last I checked, and they're mostly healthy and active and eating whole foods.  So it's mostly healthy omnivores vs. healthy vegetarians vs. healthy vegans.  Because all of these people live in Canada and the U.S., that removes a lot of the cultural differences.  Because the studies are so large, it's possible to filter out for different ethnic backgrounds.  It's also to look just at sub-sets (such as the thousands of California adventists) to reduce the chance of environmental differences playing a role.  Adventists are a particularly interesting group to study because they tend to live healthy overall lifestyles no matter what they eat, but that many of them are vegetarian, and many of them are vegan (whereas in most other groups the vegetarians and vegans would be much smaller sub-sets).

The Adventist studies suggest that healthy vegetarians have slight advantages over healthy omnivores, and that healthy vegans have significant advantages over both omnivores and vegetarians.  The vegans suffer less heart disease, less diabetes, less cancer, and less all-cause mortality than the other groups.  Here's a link:  https://publichealth.llu.edu/adventist-health-studies  Off-hand, I'm not aware of any health metric in the Adventists studies where the vegans didn't come out on top.

As to your second point, rehydrating of fossilized human stool is now suggesting that many (most?) pre-agrarian societies were mostly plant-based.  That seems to be true in the cradle of civilization in Africa where so much of our evolution occurred, for example.  There's new evidence that we've been cooking grains for far longer than previously believed, too.  (source:  https://www.youtube.com/watch?v=bgc-6zZj034)

I used to think this way.  But it's a dangerous way to think, IMO.  Replace that statement with heroin, or sex, or child porn, or whatever.  I believe we should be able to give *anything* in our lives up, given a good enough reason.  Addiction to anything is a very bad thing, IMO.

I ate mostly meat, dairy, eggs, and refined carbohydrates for the first 40-ish years of my life.  Now I eat a diet that includes no meat, no dairy, no eggs, and very little in the way of refined carbohydrates.  So I've done an almost complete 180 degree turn in my diet.  And there was a time that, just like you, I couldn't imagine giving it up for 2 weeks, let alone a lifetime.  But then I did, once I realized there was a good enough reson to do so.  I try to be open-minded in all things, and have done several 180 degree turns in my life once new information presented itself.

The idea that vegetarians/vegans need a lot of supplements is a commonly-stated falsehood.  All nutrients come from one of three places:  bacteria (vitamin B12), the sun (vitamin D), and plants (everything else).

Your suggestion that meat protein is superior to plant protein is a falsehood.  The fact of the matter is that the only things on the planet that are able to manufacture amino acids are plants (plants pull nitrogen out of the atmosphere, create amino acids, and then combine them into proteins).  The idea that animal protein is superior to plant protein is an idea that was first (and falsely) introduced in the 1970s book "Diet For a Small Planet", a book that ironically was encouraging people to eat a more plant-based diet.  The author of the book introduced the idea in the 1970s, and then recanted it in the 1980s.  She lacked the credentials to make the original claim, as it's an anti-scientific argument to suggest that meat protein is in any way superior.  Those that try to suggest it is do so by arguing that meat has an idealized amino acid ratio (a ratio that some plant foods also have, BTW).  But we now know that's irrelevant, as we've since learned that the body breaks apart the individual amino acids as food is processed and stores the individual amino acids for the body to combine when and how it needs to.

Meat protein is the lowest quality protein because its wrapped up in cholesterol and saturated fat.  Our bodies don't need to consume cholesterol because we manufacture it internally, and unlike carnivores (and most omnivores), humans have no mechanism for getting rid of excess cholesterol.  Researchers have tried and failed to give heart disease to dogs in controlled conditions, whereas it's almost effortless for humans to get heart disease from the same diet.

One study looked ath nutrient deficiencies in North Americans and found that the average vegan was deficient in 3 essential nutrients.  Before you say "I told you so!", note that the very same study found that the average omnivore was deficient in *7* essential nutrients.

And that makes sense.  Plant-based foods tend to have a lower caloric density, and far more nutrients per calorie, than foods of animal origin.  So on a plant-based diet you'll get more nutrients for the same number of calories.  People should be eating a diverse array of foods no matter what diet they choose (eat the rainbow, as the mantra goes).  So if you're eating the rainbow and eating plant-based foods then your odds of having a nutrient deficiency is very low.  When I was an omnivore, I was always running out of calories by the end of the day, meaning I was still hungry and hadn't got in all the nutrients I needed.  On a whole-food, plant-based diet I get to eat as much as I want while maintaining my weight.

So please be aware that you're spreading misinformation that has no basis in science whatsoever.

Following what your body craves serves you well...  until it doesn't.  I have friends of the family who seemed to do great eating mostly hamburgers and hotdogs...  until they all started getting by-pass surgeries.  Following one's cravings is a bad strategy in general:  a heroin addict craves heroin, but that's not because their body needs more heroin for optimal health!  There's lots of evidence that the process of digestion creates compounds that triggers cravings in the body, and that this mechanism has nothing to do with the body's nutrient needs whatsoever.

As for the morality, a very small number of animals are living a relaxed and safe life roaming meadows.  Humans have about 70 billion animals in the animal agriculture system at any given time, and the overwhelming majority of those are factory farmed in cramped and squalid conditions that are so bad they have to pump them full of antibiotics just to keep them alive.

How is a vegan lifestyle more expensive?  I can get a gigantic bounty of fruits and vegetables for a pittance.  The only time veing vegan is expensive is when you choose to incorporate processed foods like imitation meats, and such like.  Fruits and vegetables and nuts and seeds are ridiculous cheap compared to meat, especially when comparing organic produce vs. organic/grass-fed/freerange meat!  In an apples to apples comparison, being vegan is distinctly cheaper, especially when one considers how nutrient poor meat/dairy/eggs are per calorie.  When I went plant-based, my food bill dropped precipitously (despite the fact that I was eating more food in total).

That's actually the strongest reason to be vegan of them all.  The animals you eat consume hundreds of times more plants than you would if you swapped those animal products out of your diet for plant-based foods.  I actually have found the research you're referring to as not persuasive:  my take on it is that some plants are able to be reactive to their environment, not that they are conscious in any way.  But if I say that recognizing that if they were conscious that it would actually strengthen my overall argument.  A cow may eat 500 times as much food as you get out of eating the cow, which sounds like a disaster for those concerned about the poor plants.  The argument that plants feel pain is often held up as an anti-vegan argument, but it's actually the most pro-vegan argument of them all.

It seems like this doesn't take a holistic look at it.  For example, is it including all the energy (and water, and land, and, and, and...) that the food animal is consuming?  I very much doubt it.  Animal agriculture, direclty and indirectly, is now consuming 35% of the world's ice-free land, huge amounts of our grain, and tremendous amounts of our fresh water.  Check out this link, for example:  http://news.cornell.edu/stories/1997/08/us-could-feed-800-million-people-grain-livestock-eat

What's with the necrobump?

Anyway, as vegetarian for some 23-24 years I couldn't care less if any of diets are healthy or not - live and let die, and all that jazz - just don't fucking touch my cheese.

False.  Animals don't create nutrients, they get them from eating plants.  When you point to vitamin B12, that's a self-defeating argument as vitamin B12 isn't created by animals either, it is produced by bacteria.  Animals traditionally got it from eating plants from the ground, and drinking water on the ground.  These days, they give vitamin B12 supplements to factory farmed animals as they'd be deficient otherwise.  So when you eat factory farmed meat (which is the overhwhelming majority of meat that most people eat), you're actually eating supplemented vitamin B12 yourself.

Plant-based foods can have every nutrient you can imagine (even B12 in small quantities, as is the case with some seaweeds, and vitamin D in the case of UV-exposed mushrooms), and plant-based foods on average have far, far, far more nutrients per calorie than animal-based foods.

Your claim that humans need meat is also false.  We used to think that our evolution started to kick off when we started eating meat (which importantly acknowledges the fact that much of our evolution was mostly meat-free), but new evidence suggests it was actually when we started cooking starch-based foods.  That's what gave our bodies the extra calories for our brains to grow.

As for iron and calcium, dairy actually reduces the amount of calcium in the body (digesting dairy requires it to pull calcium out of the bloodstream to process the dairy-based foods), and plant-based foods have lots of iron (and if consumed with vitamin C rich foods, it's as bio-available as any other source).  The heme iron in red meat is actually not good for humans at all.  An interesting element of plant-based iron is that if the body is iron deficient then it absorbs it more readily, and if it has an abundance of iron then it absorbs it less well.  The body has no such defence mechanism for the heme iron common in red meats, which it absorbs readily even if the body has too much iron already (and too much iron in the body can be a very bad thing).