The best source of protein is Whey..and that ain't meat.
I can't eat Whey, so I eat Soy Protein Isolate. Again, no meat. ANd tons of protein. Way (pardon the pun) more then anyone who doesn't lift heavy weights is going to need.
But meat can be awfully tasty.
In addition to being estrogen like, overconsumption of soy isoflavones have also been linked to thyroid, bladder and kidney problems in some people.:2 cents: