The original diet
Even the animals were vegetarian.
29 Then God said, “I give you every seed-bearing plant on the face of the whole earth and every tree that has fruit with seed in it. They will be yours for food. 30 And to all the beasts of the earth and all the birds of the air and all the creatures that move on the ground—everything that has the breath of life in it—I give every green plant for food.” And it was so.
Just googled this to find more supporting information.
Indeed, “carnivorous” animals can live primarily on vegetarian diets, even lions.