By Anna Wlodarczak-Semczuk

Cannibalism became taboo in human societies not out of instinctive aversion but because it is ⁠harmful to populations who practise it, scientists from Poland and the Czech Republic have found.

Michal Misiak of the ⁠University of Wroclaw and Petr Turecek of Charles University in Prague used a mathematical model ⁠to show that the long-term practice ‌of cannibalism can lead to population collapse by causing illnesses in those who eat other people.

"We looked at the human body as a potential source of food, analysing both energy gains and hidden costs," Misiak said in a statement released on ‌Wednesday by Wroclaw University.

"From a caloric perspective, a person turns out ​to be ‌an average meal ... The key problem, ‌however, lies elsewhere: the risk of infection. Pathogens have an easier task because they end up in ⁠an organism with almost identical physiology."

Their model ‌shows the risk of ⁠disease rises exponentially when cannibals ​consume other cannibals, as even cooking ‌does not eliminate prions, or misfolded proteins, that can cause fatal neurological diseases.

One of these, kuru, was once common among the Fore people of Papua New Guinea, ​who cooked and ate their deceased relatives, believing ‌they ‌were freeing the spirit of the dead person.

The researchers said these risks probably contributed ‌to the emergence of ​one of humanity's strongest taboos, which was based at least in part on its protective function.

"Taboo acts as an evolutionary safeguard," Misiak said. "Our results ⁠suggest that this was a biologically justified response to the ‌growing risk of epidemics. Communities that didn't curb cannibalism simply didn't survive."