Having been commanded to bring animals on the ark, God proceeds to command Noah:
As for you, take for yourself some of all food which is edible, and gather it to yourself; and it shall be for food for you and for them. (Genesis 6:21)Since Noah would end up spending about eight months on the ark, he would need to gather an enormous amount of food. Not only would he need food for himself and his family, but he would also need food for all of the animals.
The type of food which Noah would need to gather does not seem to have been as wide in variety as might first be thought. Noah did not have to worry about gathering pile after pile of different kinds of meat. Scripture seems to indicate that prior to the flood, God had not permitted man or animal to eat meat. At the creation of the world, God said concerning food:
Then God said, "Behold, I have given you every plant yielding seed that is on the surface of all the earth, and every tree which has fruit yielding seed; it shall be food for you; and to every beast of the earth and to every bird of the sky and to every thing that moves on the earth which has life, I have given every green plant for food"; and it was so. (Genesis 1:29-30)There is no clear indication that this diet changed at the fall. Death, however, did come into the world. Shortly after the fall, God made Adam and Eve garments of skin (presumedly from an animal). Abel also offered to God an animal sacrifice. However, nowhere is it indicated that God approved of a diet change. Nowhere is it indicated that man began eating meat. Admittedly, this alone would not be the greatest of evidence of a meatless diet, but there is one additional piece of evidence which makes the whole matter quite clear. After the flood had ended, God said to Noah and his sons:
Every moving thing that is alive shall be food for you; I give all to you, as I gave the green plant. (Genesis 9:3)This verse strongly suggests that, before the flood, man had not yet been permitted to eat meat. It was only after the flood had ended that man was permitted to eat meat. It seems that the assumption could also be made that it was not until this time that animals were permitted to eat meat (this could also have some connection to Genesis 9:2, where it appears that man's relationship toward animals changed).
It therefore seems incredibly likely that all the food which Noah brought on the ark was "vegetarian" in nature (at the very least, the food which Noah brought for himself and his family did not include meat). This would also explain why Noah had to gather the food. Concerning the animals, Scripture indicates that they came to Noah (Genesis 6:20). That is, animals could walk/crawl/etc to Noah. Plants, however, are obviously incapable of walking. And so while Noah seems to have been spared the trouble of tracking down every animal species on the planet, he was required to gather sufficient food to feed him, his family, and the animals.
Noah's Obedience - Genesis 6:22
The Animals Come To Noah - Genesis 6:19-20
God's Covenant With Noah: Promised - Genesis 6:18
State Of The World (2469 BC): 120 Years Before The Flood - Genesis 6:3
God's Ark Which Noah Built - Genesis 6:14