The preliminary verdict is in: Meat can contribute to cancer. But lets not forget about processed foods in the process.

...The essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine threonine, tryptophan, and valine. For meat eaters, these essential amino acids are found within meat, but vegetarians need to make sure that they make complete protein meals to get these amino acids...