Is meat better or worse for your diet?

My boyfriend is convinced that meat is bad for your body and can really severely screw it up. My uncle is 93 years old and he eats just like everyone else does, he drives, he is completely aware of what is going on, and has a memory like an elephant. My boyfriend says that meat makes him feel bad, but Im thinking that may just be an excuse not to eat it. He will not eat ANYTHING with animal byproducts, but he will eat eggs....which makes no sense lol. (BTW he is NOT a vegetarian or against meateaters) I think that the way the meat is prepared is what makes it healthy or unhealthy. He went so far as to even mention how they raise the chickens and all that other stuff. We are really into organic foods, but Im thinking this might be going a little too far. Does anyone know of a website that I could refer him to, or a book, that tells what good things meat does for your body, and what bad side effects are possible if you do not have it in your diet at all? Thanks for your help!