Instances of individuals who have developed a liking for human flesh are heard of occasionally. Such individuals are called cannibals. Besides being illegal and culturally taboo it is the leading cause of transmissible spongiform encephalopathysuch as Creutzfeldt-Jakob disease and Kuru. TSE's are incurable and invariably fatal. There is plenty of evidence that the Aztecs ate humans. Archaeologists have found human bones with human teethmarks on them in Aztec ruins.

There is a famous book called Alive!, based on actual events, where stranded survivors of a plane crash ate the dead bodies to survive.

You can eat people but it's generally not accepted.