I'm more than half way through The Hungry Soul, by Leon Kass, M.D. (and he's not going to let us forget it). The basic argument is the same kind of sloppy pseudo-Aristotelian nonsense we see in the more honestly irrational religious/conservative public intellectuals (e.g. the Intelligent Design crowd, the Don't Tinker with the Successful Institution of Marriage crowd, etc.)
Kass promises in his Introduction that his conclusions about morality and the good will be drawn from universal human conventions -- conventions like the abhorrence of cannibalism. Yet in Chapter 3, Host and Cannibal, we discover than many major civilizations engage in cannibalism. Kass, of course, informs us that this is degrading and inhuman, but doesn't seem to notice that the widespread practice of cannibalism is a major piece of evidence against his thesis. He regards it as an illustrative example, when in fact it has to be explained away very convincingly if the idea that an abhorrence of cannibalism is essentially human.
Similarly, we learn in Chapter 4 that the natural direction of progress in table manners is toward more decorum, because in Europe, there was a change from eating with one's hands to eating with utensils. We learn later that China and Japan (which acquired these customs under a Classical and Feudal system, respectively, and were certainly more primitive than Europe in some respects until recently -- e.g. industrialization, etc.) are "farther along" because, like Chimpanzees, they eat with sticks instead of sophisticated metal tools. (Kass, of course, does not mention the Chimpanzees.) When eating practices move in the other direction, this is not evidence against Kass's thesis -- instead, it is a sign of cultural decadence, when people can eat ice cream shamelessly in public.
Nor are the howlers restricted to things Kass really, really wants to be true. In Chapter 1, we learn that to an animal, food is material and only material, and its form or kind is ignored. We also learn that a rabbit recognizes the form of the carrot (because it seeks any carrot, and therefore seeks a kind). Later, Kass brings up Rousseau's observation that animals are often incapable of seeing beyond the form of food to the nourishing underlying material -- a cat may starve in the presence of fruit, or a pigeon in the presence of meat.
In Chapter Three, we learn that cannibalism is natural for many animals (the example of certain tadpoles is given), but also that cannibalism is an uniquely human sin, by which we can be worse than the animals.
His argument for the existence of forms is pretty good anyway, though.