Obola isn't too far from one of the reasons for cannibalism. His dog eating sprang from his step father's belief in [pagan] animism.
The folks in New Guinea generally practiced it on deceased relatives to "keep their loved ones near to them", aka "endocannibalism".
Otherwise, it was probably to "gain the powers" of their vanquished enemies. And adding insult to injury, aka "exocannibalism".
The problem with eating people, especially other cannibals, is contracting CJD (human version of Mad Cow) from eating others infected with CJD.
I once knew a guy whose parents retired to the South Seas some place. The local museum had the remnants of the boots worn by the last guy (a non-native, late 1800s) to be officially eaten on the island, allegedly by "accident" after a "misunderstanding".
Queen Victoria had forbidden the practice.
That may have been the Fiji islands where a missionary named Reverend Baker was killed & eaten; the cannibals had never seen boots before & boiled his for hours trying to make them tender.
To this day the worst insult to a Fijian is, “Go eat Mr. Baker’s boots!”