[Weatherlight]

I wouldn't try to hide it from the trip leader now. Everyone will find out the moment you try to excuse yourself from eating a corpse, anyway.

Explain now that you don't eat animals, discuss methods of respectfully refusing animals on a plate, and ask for more detail about what foods will be available.

People have very different reactions to things like being told someone is veg*n when they don't have a clue what that's about, never met a veg*n before, or perhaps not even heard of it at all. I've had that in South Korea, from late 1999 to late 2003. Some people were polite, respectful, confused, and intrigued :P They wanted to know more about why I wouldn't eat meat; they also asked what sorts of things I could eat and liked to eat, and looked over what they had available, trying to accomodate me.