First off, I don't really see it as a natural diet. Insofar, as if we were living in a completely natural setting (hunter-gathering) meat would be absolutely necessary for survival.
Second, soy is horrible for the environment. More land is cleared every year for soy production than for beef. Also it is very depleting to soil, as well as corn.
Third, I don't buy meat. Or soy. But I will eat meat if it is free (hunted, stolen, roadkill, home raised, etc.), but I won't eat soy.
