Again, it's accepted facts that are taught to everyone. You should know it. There's no reason to source common sense.

That's a load of fud. Any kid's school book on health and the nutritional needs of humans says that you're wrong as a flat earther. Humans can only get B12 from animal products naturally and from supplements/injections artificially if you don't eat animal products.

B12 comes from bacteria, animals don't produce it - https://en.wikipedia.org/wiki/Vitamin_B12 "No fungi, plants, or animals (including humans) are capable of synthesizing vitamin B₁₂: only bacteria and archaea have the enzymes needed for its synthesis."

You could do the more natural thing, and eat dirty vegetables, unwashed mushrooms and such and get A TON of B12. Instead, vegans sanitize their food and then get the B12 through fortified foods and supplements.

Nutritional yeast: http://nutritiondata.self.com/facts/custom/1323565/2

We're not a natural culture; we cook, wash, and process our food in other ways. Even non-vegans can be deficient in B12; only certain kinds of meat (shellfish and ruminants) have it naturally, you can eat several kg of chicken each day and still be B12 deficient (unless the chickens were given supplements). Many food products (especially commercial vegan products) are fortified with it.

In the US, the biggest meat-eating country in the world - 39% of people have low B12 https://www.ars.usda.gov/news-events/news/research-news/2000/b12-deficiency-may-be-more-widespread-than-thought/ and show symptoms of deficiency. So, vegans are not the only ones who could benefit from B12 supplements.

But: Is there something wrong with not having all-natural products? 76.2% of Americans are on medication, 50% of them take vitamin pills; Europe varies, Western and Northern countries see levels in the 60%-70% range while Eastern countries see levels in the 25-50% range). Neither are natural, and much of the medical epidemic relates to poor diet.

I'll also bring up six extensive scientific studies across different nations all found people following low meat consumption diet live longer than those who consume lots of meat, and those who consume no meat live even longer. German and American studies also found that long-term veganism yields even more positive effects than short term. https://academic.oup.com/ajcn/article/78/3/526S/4689992

So why is it that supplementation only gets called out as a bad thing when vegans do it? Basically, everyone in modern society consumes them via fortified foods in order to balance out their diet, by eating farmed animals who have had supplements in their feed, or other means; and if they don't, they're generally deficient. If we actually did live more naturally and gave up things such as food sanitization, then B12 deficiency wouldn't be an issue for anyone, vegan or non-vegan. We're not going to live naturally.

...which ones

In general, the composition of plants is a lot more diverse than that of meat. Further off from what you need, individually, but you have all the spikes you need to balance it out, if you do the math. 

The "best" diet is one thats varied/balanced, I think.

If you're not measuring it, this is probably true.

B12 comes from bacteria, animals don't produce it - https://en.wikipedia.org/wiki/Vitamin_B12 "No fungi, plants, or animals (including humans) are capable of synthesizing vitamin B₁₂: only bacteria and archaea have the enzymes needed for its synthesis."

You could do the more natural thing, and eat dirty vegetables, unwashed mushrooms and such and get A TON of B12. Instead, vegans sanitize their food and then get the B12 through fortified foods and supplements.

Nutritional yeast: http://nutritiondata.self.com/facts/custom/1323565/2

We're not a natural culture; we cook, wash, and process our food in other ways. Even non-vegans can be deficient in B12; only certain kinds of meat (shellfish and ruminants) have it naturally, you can eat several kg of chicken each day and still be B12 deficient (unless the chickens were given supplements). Many food products (especially commercial vegan products) are fortified with it.

In the US, the biggest meat-eating country in the world - 39% of people have low B12 https://www.ars.usda.gov/news-events/news/research-news/2000/b12-deficiency-may-be-more-widespread-than-thought/ and show symptoms of deficiency. So, vegans are not the only ones who could benefit from B12 supplements.

But: Is there something wrong with not having all-natural products? 76.2% of Americans are on medication, 50% of them take vitamin pills; Europe varies, Western and Northern countries see levels in the 60%-70% range while Eastern countries see levels in the 25-50% range). Neither are natural, and much of the medical epidemic relates to poor diet.

I'll also bring up six extensive scientific studies across different nations all found people following low meat consumption diet live longer than those who consume lots of meat, and those who consume no meat live even longer. German and American studies also found that long-term veganism yields even more positive effects than short term. https://academic.oup.com/ajcn/article/78/3/526S/4689992

So why is it that supplementation only gets called out as a bad thing when vegans do it? Basically, everyone in modern society consumes them via fortified foods in order to balance out their diet, by eating farmed animals who have had supplements in their feed, or other means; and if they don't, they're generally deficient. If we actually did live more naturally and gave up things such as food sanitization, then B12 deficiency wouldn't be an issue for anyone, vegan or non-vegan. We're not going to live naturally.

Well, here are examples of longterm vegans:

http://thevegantruth.blogspot.ca/2013/03/a-compilation-of-long-term-vegans-our.html

Stuff has already been said. But lets continue with Protein. What are easy sources of protein in plant sources?

And by Protein I mean:

Histidine

Isoleucine

Leucine

Lysine

Methionine

Phenylalanine

Threonine

Tryptophan

Valine

Arginine

Cysteine

Glutamine

Glycine

Proline

Tyrosine

I genuinely would like to know. I am sure they can be found, but easily? I don't think so.

thevegantruth? 😹 Yeah, you can have an unhealthy diet a long time before the reaper comes calling or your body starts to pay the price for it. Also, I'm not gonna take the word of cultists using their own experience as evidence.

Here's a study/article by legit people.

https://academic.oup.com/ajcn/article/89/5/1627S/4596952

Basically without living in 1st world country and taking sufficient supplements, it's extremely unhealthy because you wouldn't be getting the basic nutritional needs that the human body needs. Even then, you would need to get regular blood work done in order to adjust your diet/supplement intake according to what you're lacking. If a person goes long enough with vitamin and mineral deficiencies, it can easily cause permanent neurological damage and organ damage. Veganism is a moronic diet that's unhealthy but if you want go by that numbnut diet, by all means. Kids are eating tidepods for clicks these days so what's the worse that can happen.

I was showing you an example of providing sources, your post made a claim that long-term vegans had to stop, and I should you that there were vegans who have lived for over 30 years with that diet. I also don't understand what the issue is with taking supplements, supplements exist specifically for that purpose. Also, I don't necessarily promote going all vegan, but I do believe that meat consumption is way too high as it is, considering its environmental effects:

http://cases.open.ubc.ca/environmental-impact-of-meat-consumption/