Genesis 1:29

Man's first food was solely fruit and produce from trees. Man's guilt subsequently introduced the use of bread. The posture of his body shows forth the state of his conscience. As long as man's conscience did not reproach him, innocence raised him up toward the heavens to pluck his food from the trees. Once sin had been committed, it bowed man down to the soil of the earth to get grain. Still later the use of meat was added.

I myself hold with those who, considering the words, "Male and female he created them, saying, 'Increase and multiply and fill the earth,' " interpret them as referring to visible and bodily sex. This is clear, in view of what follows: "And God said, 'Behold, I have given you every plant yielding seed which is upon the face of all the earth, and every tree with seed in its fruit; you shall have them for food. And to every beast of the earth, and to every bird of the air, and to everything that creeps on the earth, everything that has the breath of life, I have given every green plant for food.' " Note that both male and female used the food for the body that the other animals used. They received fitting sustenance from it. This was necessary for the animal body lest it suffer from hunger. But it was received in a certain immortal way and from the tree of life, lest they die of old age. I would never believe that, in a place of such great happiness, either the flesh lusted against the spirit or the spirit against the flesh, and there was no internal peace.… We conclude, therefore, that there was no carnal concupiscence in that place. Such was the manner of life that all necessities were taken care of by the proper functions of the members, without arousing lust.

We note, however, many wild beasts do not eat fruit. What fruit does the panther eat? What fruit makes the lion strong? But nevertheless these creatures, when submitting to the laws of nature, ate fruits. And likewise when the [first] man changed his way of life and voided the limits set upon him, the Lord, after the flood, knowing humans were wasteful, allowed them to use all foods: "Eat every food as if it were edible plants." Since [humans] were allowed this [concession], the other animals [also] received the liberty to eat. So the lion is [now] a meat-eater, and the vulture looks for carrion.But vultures were not yet circling above the earth to find carrion when the animals originated; nothing created nor imagined had yet died in order to be food for the vultures. Nature had not yet been divided; everything was completely fresh. Hunters did not capture prey, since people did not yet practice this. The beasts did not yet tear apart prey, since they were not meat eaters yet.… So was the first creation, and to this creation will be restored after this [age]. Humans will return to their original creation, rejecting hostility, a life encumbered with care, the slavery of the world to daily worries. Once they have renounced all this, they will return to that utopian life which is not enslaved to the passions of the flesh, which is freedom, the closeness to God, a partaker of the life of the angels.