It was not until the 1985 film Return of the Living Dead that zombies start snacking on brains, with one zombie specifically explaining that eating brains “takes away the pain of being dead.” The 1992 Simpsons episode named Treehouse of Horror segment Dial Z for Zombies itself was a spoof of Return of the Living Dead.
When asked, Romero himself has no idea where the brain-eating idea came from and in a 2010 interview with Vanity Fair, when asked about the link between zombies and brains, Romero very bluntly explained that:
“Whenever I sign autographs, they always ask me, “Write ‘Eat Brains’!” I don’t understand what that means. I’ve never had a zombie eat a brain. But it’s become this landmark thing.”
Romero has always maintained that the focus of his movies isn’t the zombies- it’s us, or rather our reaction to them and that the zombies and how they function isn’t important. An idea that is shared by the many creators of media inspired by his work.
Dan O’ Bannon writer and director of Return of the Living Dead once commented that Zombies feast on brains of the living because it makes them feel better by easing their pain.
Jack Flacco validated O’ Bannon’s theory by stating, brains
“provide zombies with the necessary endorphins to dull the pain of Rigor Mortis brought about by decomposition. The more brains, the less pain” (2013).
However this modern addition to the myth seems more humorous than realistic.
Cannibalism is not universally practice due to the fact that it could be deadly. The human brain is more contaminated with prions than any other body part. Examples include kuru, Creutzfeldt-Jakob disease in humans, and mad cow disease in animals.
The Fore people of Papua New Guinea, for example, had a tradition involving cooking and eating the brain of a deceased loved one as a way of freeing their spirit. However, in the 1950s, this led to an outbreak of the fatal prion disease kuru, a neurodegenerative disorder characterized by tremors and uncontrollable laughing fits that ends up with death. While a lot of infectious or potentially infectious material can be destroyed by thorough cooking, prions cannot. The only way the Fore got the disease under control was to give up cannibalism.
Besides, have you ever tried to get to someone’s brain with just your teeth and fingers as weapons? Skulls are hard for a reason. Brains are hard to get too, generally, and the zombies would starve if that was their main food.