You don't need meat. You need amino acids. It's very hard to get enough amino acids to properly grow, especially at that age. "Prove that humans need meat to survive". Right?
Also, as far as obesity goes. I have provided multiple articles on how obesity at the very LEAST is an aid and eventually leads to multiple diseases. You think being obese has zero side effects and can cause no issues. I doubt you even read the articles that I have posted. Also, your claim of "countless hours" of research is a joke. People dedicate their lives to this. You eat you're Canadian "putine" on your lazy boy recliner, google a couple of things, and think you know what you are talking about. In actuality you should really stop talking at this point.
To say humans need meat is a completely ignorant statement. Nutritional value? Please tell me what nutritional value a steak or a piece of chicken has that you cannot get from a vegetable or some sort of dairy? Go ahead...