I get huge munchies pretty much as soon as the peak effects are ending. As soon as I come back from that psychedelic peak my body wants sustenance.
It doesn't matter what drug it is, they all do that; even stimulants. I eat a couple hours before a trip because I have a high metabolism and I eat frequent meals throughout the day. If I don't eat before a trip, my blood sugar level will be low, I will be hungry and the trip will suck and be kind of painful...