Protein is a meme or an advertisement/marketing word.
Protein deficiency doesn't exist unless you are starving, by living on like 400 calories a day. If you eat enough calories, there will be enough protein tied to the food. Protein is a building block of life, all life needs protein to grow, and all life follows the same rules of nature, for a structure to grow, both flora and fauna(plants and animals) obey certain "energy rules", but basically if you meet your energy needs by eating enough calories, you will meet your protein needs.
It's maybe the case, that you need to eat a higher volume of plant-based food, to get the same amount of calories/protein that you would get from meat/processed food.
But high plant sources of protein are found in: beans,
buckwheat, this basically has the same nutritional profile of meat, except it's healthy(I eat a lot of this), lentils, nuts,
tofu.
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A man needs about 50-60 grams of protein a day(not 100, or 300) High protein diet, ages and kills you prematurely, also drastically increases chances for cancer and various of other degenerative diseases.
[video=youtube]https://www.youtube.com/watch?v=7rNY7xKyGCQ&t=1s[/video]
Good quality(evidence-based) vegan channels are here:
Nutrition Facts
Mic The Vegan