I'm not, but I have lots of acquaintances who are, so I frequently end up eating veggie anyway on a backpacking trip.
Most commercial manufactuerers of dehydrated bp food have a number of veggie offerings - some of them even don't suck. So I do use those. Lipton sidekicks, Ramen, are all good bets as well, particularly if you can find some dehydrated vegtables to add to them. I'm quite fond of kikkoman miso soup packets, which I often take as well. Oatmeal of course. And instant potatoes. If you eat fish you can take retort tuna packages. pop tarts, etc. etc.
snacks: dehydrated fruit (mangoes, craisins, dates, etc.) rye crisps, pitas, peanut butter, smoked almonds, trail mix, a nice block of parmigiano reggio, cliff bars, snickers bars, etc. etc..
Loc: Eastern MA, USA
I'm not a vegetarian, but I do use some vegetarian-friendly foods while backpacking. One of the easiest items to find in the health-food section is dry TVP granules. They absorb some flavor from other ingredients in the recipe. Add TVP to nearly anything, from the Lipton Noodles that Phat mentioned to oatmeal. Other foods: nuts, dried fruit, etc. What Phat said!
In many cases with the recipes I develop is that the only reason they are meat eater friendly is the process of adding in meat. In other words, meat is easy to leave out and or one can use TVP or beans instead
For commercial meals you can have good luck with Mary Jane meals and some Backpackers Pantry.
Freezer Bag Cooking, Trail Cooking, Recipes, Gear and Beyond: www.trailcooking.com
Loc: spotaylvania, va
im not a vegetatian but when im on the trail i dont have any meats except for bacon. potatoes with sour cream and bacon, eggs with cheese, potatoes and peas, pea soup(thick), broccoli soup(thick), an occasional cornbread, beans and so on.all the things i eat except for the potato flakes i make\dehydrate at home and i use a jet boil pcs and occasionally the group system.