They used every part of the animal they hunted to survive. However, now we have all kinds of clothes, housing and are not constantly hunted by other animals, so eating their meat is simply a luxury. Before humans figured out how to hunt larger animals, plants and grains were consumed. This was no inconvenience and the man lived well. Returning to this lifestyle would transform the world into a cleaner place and could help the world achieve an organic lifestyle, which would be beneficial to humanity.