Right, retirement home.  That's my point.  In predominantly plant-based societies, the eldery tended to live longer, but also tended to be far more vibrant.  Far from living in a retirement home, they more typically continued to contribute to their families and communities rather than be doted on.  We have this idea that the eldery are necessarily decrepit.  That's a relatively modern assumption, though.  Meat, dariy, and eggs are inflammatory, are correlated (or known to directly cause) lots of disease, etc.  As we've eaten more of these things, we beat down our defences over the years.  Your reference to retirement home says it all.

Since going on a plant-based diet, I haven't lost any weight at all.  I eat a significant amount of seeds (chia, flax, buckwheat, hemp, and sesame, all added in different ways to different kinds of meals), which have a higher caloric density than most plant foods.  There's no need to be underweight.

Again, please re-read my previous post.  The idea that there is an idealized amino acid ratio is a myth.  What's important is that you get all your amino acids in your diet over time, as the body can store excesses for later combining.  Fun fact.  As an omnivore, and as a pescetarian, I supplemented my lysine.  I was taking 6-8 lysine pills a day.  I did it as an immuno booster to fight cold sores, which I got almost immediately if I went off the pills (or sometimes even when I did take them).  I went plant-based almost a year ago, and subsequently went *off* my lysine pills with nary a cold sore.  When I still ate meat I had to supplement with lysine, and it's only now that I'm off meat/dairy/eggs that I've been able to stop supplementing.  Of course, when I was eating meat I was supplementing, since most of my meat (like most of almost everyone's meat) was factory farmed and they give farm animals this cocktail of vitamins (including B12) and antibiotics, and some of that survives right to your plate.  Meat, dairy, and eggs are immuno-suppressant in general, but being plant-based is an immuno-booster, and I have chosen to particularly highlight plant foods that contain beta-glucans which further accentuates that.

Back to your point.  Ancient societies were pretty good at not eating poisonous foods.  And one of the the things you don't appear to understand, is that the plant-based foods they ate don't exist anymore (either because they've gone exctint, or been selectively bred for so many generations that they're pretty much unrecognizeable).  Broccoli used to have a tiny flower on a gigantic stalk, but we've bred it to be the other way around.  Ancient peoples didn't originally eat many things like almonds or corn, they most ate fruit and flowers, and the fruits they ate were less sweet and more fibrous with way more protein than the modern alternatives.  Did you read that they used to eat fruit and assumed it was something akin to modern apples and pears?  Keep reading, the only way to eat a truly traditional diet is to eat a mix of fruit and vegetables, as the fruit they used to eat were nutritionally about halfway between a modern fruit and vegetable.  And if they ate something and got sick, word got around and people learned not to eat those things, so the ones that were poisonous versus the ones that were health-promoting were pretty easy for them to figure out.  :)

And again, your point about protein is a non-starter.  Because on a plant-based diet you can eat more total food to get the same amount of calories, they got piles and piles of protein.  It's essentially impossible to not get enough protein on any diet, even vegans get 50-100% more protein than is ideal for health.  I struggle to keep my protein intake down, and instead to increase my fibre intake.  Most people get twice as much protein than they need, but should be getting 5-7 times more fibre than they do (most people are about halfway to the recommended minimum, and the minimum is about halfway to the ideal level).  And since almost all plant foods (including all commonly eaten ones) contain every essential amino acid in different ratios, eating a variety of the plant foods in a given area almost always gave them enough of each.  As for lysine, in our quest to make fruit taste better, and vegetables easier to cultivate, we may have actually selectively bred plant based foods to have less lysine.  But that wasn't a problem for ancient peoples, and as you correctly said, it's also not a problem for modern people if you know what's in your food and make adjustments if there's a need to make one.  I signed up for cronometer.com, which is a website that you can plug your food every day into and it will collate and report to you the nutrients you consumed daily, weekly, monthly, etc.  So if you really want to make sure you have no deficiencies, it's a great resource.  I actually recommend it more strongly for omnivores, as they're the ones most likely to suffer nutrient deficiencies, since meat/dairy/eggs have a lot fewer nutrients per calorie and (unless you want to be overweight) you'll get far fewer nutrients in your diet as an omnivore as you will on a plant-based diet.

Again, this is not a matter of debate.  As we do things like rehydrate fossilized human stool for analysis, we can know exactly what people ate.  And it wasn't mostly mastadon.  We're seeing 98%+ plant-based diets in most ancient cultures.  And that's a wildly anti-cancer, anti-inflammatory way to live, as science is demonstrating.

It´s ok if you think differently, but everything I said I learned directly from them, and them being true vegans. I´d rather trust in statements from people who actually follow a true vegan lifestyle than from dubious internet articles.

Just as a side note, they´re vegans for religious and phylosofical reasons, not for health-related reasons.

Could you link a source for that 98% stat (specifically for anything pre-agriculture. That early agricultural societies mostly ate what they grew is both evident and irrelevant to the point.) I did not find any reliable souces on that. Thanks!

Anyways, back to the subject. You assume that prehistoric humans had access to alternatives to the mostly unedible predecessors of our modern crop. However, there is a reason why said ancestors were unedible in the past - anything but the fruit of the plant is something said plant does not want to get eaten, and they generally have some form of deterentto prevent animals from eating them - be it poison or simply bad nutritional value. Any modern animals that consume, in big part, natural vegetable matter has specifically evolved to surcomvent these hurdles. Rats, for example, can develop their caecum to digest fibres, if their environnement makes it necessary. Humans have nothing of the sort. Instead, we evolved crops to be increasingly fitting to our digestive capacities, removing poisons from beans, almonds, etc... As well as reducing fibers and increasing digestible sugars in roots, stems and leaves (which, in my opinion, is quite awesome.) 

I wouldn't suggest you trust random internet articles over anecdotal evidence from trusted friends, but I would suggest you trust well designed and respected scientific studies with good methods and controls over anecdotal evidence.

However, you suggested that someone considering going plant-based should expect tonnes of doctor's visits and to take piles of supplements.  That has been the opposite of my experience.  And unlike your friends, I have a health and wellness approach to being on a plant-based diet, which perhaps explains their different experience (as they may not be avoiding processed foods, or embracing whole foods, to the degree that I am).

I'm on a strictly plant-based diet, and the only supplement I now take is vitamin D.  When I was an omnivore I took a pile of supplements: I directly consumed vitamin C, vitamin D, a calcium-magnesium combo, lysine, and I indirectly supplemented vitamin B12 by eating factory farmed animals who were given B12 supplements.  As an omnivore I ate far less food, in the interests of weight management.  By ditching all the meat, dairy, and eggs (all of which are calorie-dense foods) I now get to eat more food in total, I get more nutrients per calorie, and the two together means I get a substantial increase in my nutrient consumption.  A varied plant-based diet covering all the bases (fruits, vegetables, nuts, seeds, grains, and legumes), combined with consuming more nutrients, has allowed me to ditch all those supplements.  And there's no shortage of evidence that getting nutrients in one's diet is far more effective than getting them from supplements, and that some supplements may do more harm than good (if you're even getting what the bottle says you're getting, which you often aren't as there's a lot of fraud and very little oversight in the nutritional supplements industry).  The only reason I still take vitamin D is that it's not even a vitamin; despite its name it's actually a hormone and it's almost impossible to get it in diet (the only way I'm aware of to get vitamin D in one's diet is to eat mushrooms that have been exposed to UV while they grew).

As for doctor's visits, I haven't even so much as had a cold since I went entirely plant-based, let alone a symptom that suggests a nutrient deficiency (despite all the nutrient deficiencies I had when I was an omnivore), so I've had no reason to visit the doctor since the switch.

You can create a bad omnivorous diet, or a bad vegan diet.  The only difference is that it's far easier to create a good vegan diet, as a whole food plant-based diet means more total food consumed (for a given amount of calories) and the opportunity to get not only more nutrients but a wider array of nutrients in your body.  It's fact that animal foods on average have more calories, and it's fact that plant foods on average have more nutrients per calorie, so you can't help but get more nutrients on a varied whole-food plant-based if you keep your calories the same.

If you focus on the easy to acquire plants like lentils, noodles, beans, peas, rice etc- will you be fine with such a diet? I have no interest in complicated vegan diet plans with fancy fruits, but shifting back to more basic plants is something that I would consider more.

Check out this video for that 98% figure:  https://www.youtube.com/watch?v=bgc-6zZj034  (As always, check the video's several citations and decide for yourself based on the cited evidence).  Another 98% plant-based population was the traditional diet of the Okinawans in Japan (1% fish, 1% all other animal products):  http://nutritionfacts.org/video/the-okinawa-diet-living-to-100/

And I don't assume anything.  With the rehydration of human stool, we can know with near-certainty what ancient peoples ate.  And it was predominantly fruit, flowers, and certain leaves, which gets around the concerns you cite.

Yes, you don't need to eat exotic foods at all.  The populations that ate the most beans (and other legumes) and grains have traditionally been the longest living and most vibrant in old age.  A great example of this is the Tarahumara in Mexico.  Their tribe was split, with some ending up living in the U.S. and some living in Mexico after the border between the two was finalized.  As the American contingent adopted the Western diet and culture, the Mexican side of the tribe (who ate their traditional diet of beans and other predominantly plant-based foods) started to live *decades* longer, whereas the American side of the tribe had a dramatic rise in incidences of heart disease, diabetes, etc.  It doesn't have to be exotic foods, if you eat a variety of common fresh fruits, vegetables, grains, and lentils, you'll be eating the diet that is associated with the least amount of disease, and the highest quality of life in old age, in a variety of populations around the world.

For decades, people have overcomplicated plant-based diets by talking about protein combining (which your body can do for you anyway).  It's actually pretty easy, so long as you keep your diet varied.

The Okinawa example is irrelevant to the context, as it is a (fairly) modern example. I did not contest that a modern vegan/near vegan diet can be very healthy - I most definately consider it to be healthier than getting excessive amounts of meat, as is common in the west. "Paleo Diet" is stupid, and even would be so if ancient humans did eat what it claimed, as it tries to solve diseases that come at an advanced age, and thus, evolution does not give a fuck about (most people of the time being either dead or unable to further reproduce beyond, let's say, 60.)

Your video does not state any specific source reffering to a 98% plant-based diet (note the 480mg cholesterol). All the sources below talk about specific cases where humans do eat grains, never stating that meat was near-absent from the menu. 

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.

A couple more arguments for the partially meat-based diet:

-Humans have a completely undevellopped caecum. All carnivore species lack a proper caecum; pretty much all herbivore mammals do have one, as well as most omnivore species (pig, rat...)

-Our closest relatives (bonobos, chimpanzees) have a partially animal diet. This diet, however, mostly consists of insects and other small animals. Such smaller animals do not need any strongly carnivorous traits to be consumed (jaw power, high stomach acidity to deconstruct bones and skin, etc...) 

-This concerns our more recent (if a few hundred thousand years can be considered recent) evolution, but we are also the world's best marathon runners. That is not a trait that would be necessary for a pure herbivore - escaping our potential predators would need more immediate speed than we could harness (humans fought back and hid alot...), and for purely energy-efficient travel, walking is still better (also gives you the time to look for edibles.) This trait in particular most definitely seems to have been used mostly to exhaust and hunt down game animals.

I rest my point, though, that what humans were eating hundreds of thousands of years ago is irrelevant, because all the modern dietary health concerns arrive at an age where our ancestors were 99% dead. Yes, I don't argue that eating meat kills us in the long run - that is, however, evolutionarily irrelevant. Domestic sheep/cows/other grazers and browsers who have their lifespan extended far beyond what they do in the wild need to cut their grass coinsumption, as it destroys their teeth in the long run. This does not mean that it's not natural for sheep to have a diet primarily of grass.

Evolution doesn't care about us, beyond a certain point, and I think we can just as well stop caring about our evolutionary traits, as well. A vegan/vegetarian diet can be healthy, healthier than eating meat each day, anyways. (I don't believe that eating fish, once a week, is necessarily unhealthy either. The rest needs to be handled as a purely ethical question.)

Financially it is.Price of meat here has really increased the past 15 years, especially fish.