I saw this movie when I was very young, in the early-to-mid 90s. All I can remember is that there was a young male protagonist (who I remember being kind of like Michael J Fox although I’m fairly certain it wasn’t him) in a dark room with an older man who was sitting on a recliner or couch. For some reason, the protagonist eats the older man’s flesh, leaving nothing but a skeleton who is still talking and sitting there like nothing happened. The protagonist was all fat after eating the man.
Okay, I’m currently a bit out of it, but Michael J. Fox was in a horror comedy called the Frighteners in which he can see ghosts. There’s also a scene in a film called My Boyfriend’s Back in which a zombie eats a young Phillip Seymour Hoffman’s flesh down to the (very cartoony) skeleton and he’s still talking like it’s no big deal.
I do believe the movie they are talking about it in fact My Boyfriends Back, I remember this scene the “boyfriend” keeps saying he doesn’t want to eat him or something but the guy won’t stop talking.
http://www.imdb.com/title/tt0107626/?ref_=nv_sr_5