A new study into ancient cannibalism seems to suggest that maneating was done for the ritual rather than because people were a bit peckish.
The study among hominins including Homo erectus, H. antecessor, Neandertals, and early modern humans. On average, an adult male human contains 125,822 calories of fat and protein, enough to meet the 1-day dietary requirements of more than 60 people.
The numbers represent a lower limit, as Neandertals and other extinct hominins likely had more muscle mass than modern humans. Still, when compared with other animals widely available to ancient man like mammoths (3,600,000 calories), wooly rhinoceroses (1,260,000 calories), and aurochs (979,200 calories).
Since humans are harder to catch than these animals it is more likely that there have to be other reasons for eating them.
Instances of cannibalism from nine Paleolithic sites, which date from 936,000 to 14,700 years ago, might be chalked up to starvation or not wanting to waste a perfectly good body that died from natural causes.
But generally the concept might be down to more magical or religious reasons, the research suggests.