I'm vegan and never have a problem getting enough protein or calories. One thing I always bring is a powdered superfood (calorie and nutrient dense) mix. My current favorite is Raw Meal, which is available in health food stores and comes in orignal, vanilla and chocolate flavors. To this I add some soy protein powder. I usually mix a bottle of it with some instant Kona coffee for my morning drink. This way i get a good meal in the morning that I can take on the go and since it's a drink mix, I find it more satisfying than eating something big in the morning.
Other than that, i just look for familiar products when I buy at resupply points or read the label. For example, there are a few vegan Thai Kitchen rice noodle packs that are really good. I like rice noodles better than the typical ramen wheat noodles and the rice also packs easier and cooks faster.
I also like to bring some miso packets - read the lable carefully to ensure what you buy is vegan - or spices to make broth or add flavor to other products. I don't usually take the prepackaged BP meals, but i have tried some of the Mary Jane's Kitchen vegan meals that I like.
Also, I think you just need to find creative ways to pack or replicate things you eat at home, like instant hummus and tortillas. On short trips, I haven taken the carton tofu products. I like adding fresh tofu to soups or my rice noodles.
Bottomline, i think you just need to experiment in general, but always make sure you have quality food and not just a lot of junk calories. I pay strict attention to the nutritional quality of my food just like I do at home. Remember your 6 basic nutrients; carbohydrate, protein, fats, water, vitamins and minierals, and make sure that you are eating healthy and balanced. Too often i see hikers just pounding in junk food and then wondering why they are so hungary. Well, it's not rocket science, it's not just about total calories, it matters where those calories come from. These same geniuses ususally insist that my "diet" is "unbalanced" or "unhealthy" or inherently "wrong." (I still find it amazing how many people will immediately begin challenging me as soon as they hear I'm vegan.)
I usually tell them the same thing I tell people who say they "tried" being vegetaraian, but they ended up tired all the time, so they resumed eating meat. As usual, the problem is they are protein deficient because when they stop eating meat, they are unaware of the plant sources of protein, so they end up eating little or no protein at all, which of course is the problem. My response, all humans need protein, so think of a vegetarian not as "someone who doesn't eat meat," but rather as someone who gets their protein from a plant source rather than an animal source.
good to remember this when you're backpacking. you need protein, so you just need to do your research and plan that part of your diet and identify vegan sources you can easily buy or pack.
Have fun, bon appetit!