How do you take the already disturbing concept of cannibalism and make it even more screwed up? Why, by making the diner what's also being served, of course!
The reason for why the Hell someone makes a meal of themselves tends to fall under one of the following three categories:
an extreme last resort due to imminent starvation
a form of Cold-Blooded Torture inflicted upon someone by a [...] [tvtropes.org]