Actually, evidence suggests only Vader and Boba ate: they both died. I'm pretty sure Han, Leia and Chewie lost ALL appetite.
As for Luke, I still consider that little bite "tasting" since he definately didn't like it. But that's a matter of opinion.
As for his lack of beardness, it is clear that the OT is Luke's journey to adulthood. He has yet to decide what side he's going to take, for he will (quoting OB1 here) "be tempted by the dark side." That ordeal will decide whether he will grow a beard eventually. Much like OB1 not having any facial hair in TPM. I'm sure that if there'd ever be sequels to the OT, Luke'd have a beard. The code commands it.