So, im going to my first training session tomorow at a local mma club, and im pretty much shitting my pants at this point

Anyways, im out of shape but the guys said to come along anyways and just going to the classes and rolling with them with them will help get me back in shape, so im wondering what should i be eating, or not be eating before i go. I mean, i really dont want to be their having ate something i shouldnt and to last even shorter than i normally would.
Im a vegetarian btw so no meat.