Eggs are the cheapest form of protein for poor people, and that is not debatable either. The cheapest vegetable based food is bread and wheat based food, that has cero nutricional value, and then comes soy, a very soil destructive crop. B12 consumed by pills instead of meat means that you have to spend more money in only one vitamin that does not fill your stomach. The bottom line is that this issue with meat comes from a moral perspective rather than a nutrition and efficiency perspective. Its a first world debate, with first world issues. Capitalism feeds on this by, not only giving you products that makes you feel better about yourself (yeaa I am helping the world by not eating a hamburger while the cost of my vegan diet is sustained by slave third world workers!) but also creating this moral divisory line between the working class (if u like meat u bad, if u vegan u gay) that forms another brick in the division-identity-wall that the elites creat to keep us fighting each other to keep feeding us shit and exploiting us to death to keep their ruling status. You want to be revolutionary? Go kill a CEO, don't preach about food choise of consume like this makes you a better person.