Raw human meat is used in taming bears, creating head pillars, and if you want to you can cook it up and eat it. Raw human meat restores 30 hunger.
Raw human meat is dropped when a player reaches 0 health, along side all of the other items the player had in his/her inventory. As of now, it also has a slim chance to be obtained through fishing.
It can be also obtained by killing yourself by resetting your character, get killed by an animal or burning yourself.