Just keep in mind you need protein. If you are exercising, you need protein. Doesn't matter if you're bulking up, or just doing endurance training.
The problem with a non-meat protein is that it's not complete. Lets say you ate a cup of peanuts, which have 10 g of protein in the amount you ate (just keeping numbers simple). You're not actually consuming 10 g of protein that your body can use. The protein is not complete. You need to consume about double the amount of protein in plant matter than you do in meat matter - and that can be hard, since protein is scarce in most plant-based foods.
I'm not saying "don't be a vegetarian." It's up to you if you eat the cow, or what the cow is made of - doesn't really matter to me. It's just you gotta watch for the protein.
If you're cutting out a lot of meat from your meals, but are willing to eat just a little, I highly recommend fish , particularly salmon. Tuna is good, but it's high in mercury, which, overtime, is bad. According to some website I heard of on the forum, if I eat 1 can of tuna, I've consumed 110% of my maximum intake of mercury for the entire week. Salmon works well - high in protein, tastes good, low in mercury. Just expensive - but that's the way it is.
Check out
www.nutritiondata.com for information on just about any food - it's a great site.
Have fun!