Complex sentence: A way to maintain this connection with earlier, less mechanic human beings was to revert to previous diet practices, and it was thought that the more primitive humans had sustained themselves on a diet closer to a vegetarian lifestyle.
Split into simpler sentences: A way to maintain this connection with earlier, less mechanic human beings was to revert to previous diet practices. It was thought that the more primitive humans had sustained themselves on a diet closer to a vegetarian lifestyle.