Van's natural diet consists primarily of plant life. Lots of different kinds of plant life. And thanks to genetic meddling, he's compatible with... unbelievable kinds of plant life!
Then again, he comes from a society in which meat, if it has to be eaten, is made to look like vegetarian food. Yes, I'm quite serious about that one.
Actually, Shenmue and I were discussing relevant points and pointless babble/facts about the Beryllians earlier. I meanwhile, am going back to my schoolwork.