I vaugly remember an experiment where a group of people were given the same diet as a gorilla, over a certain period of time. They spent more time eating than they would have normaly done, and felt hungry and lost weight. I'm not sure of all the the details, I can't remember anything more about it. It may have been a radio program, many years ago.
I remember what I do, as I figured before I heard about it that a gorilla diet would have been sufficient for a human, when you take into account muscle mass, size and weight of a gorilla against that of a human. I wish I could find the details but so far no joy.