This is a very important topic to understand as it is in direct contradiction of old-earth creationism. This is only true because the fossil record, as it is currently understood, indicates that there were carnivorous animals prior to the time of Adam. The idea of a strictly vegetarian diet prior to the flood of Noah originated from Genesis 1:29-30. This is obviously an issue, how can we have carnivorous animal fossils that predate Adam if all living beings were vegetarian?
Canon Of Reason 