Wheatgrass powder. Find one that taste good (most do). It is an above average nutritional punch I think. Take carrots and cucumbers. Munch on dried porcini (yummy) or kelp (crazy about it, it is crazily salty just so you know). Oh, kelp powder is amazing. Vegetable chips (if you got to eat chips better make it nutritionally worthy). The best thing to do is to keep yourself well nourished in adventure travels; I skip many things but definitely not veggies, eggs and nuts.

Next to your veggies might be interesting to take roasted chickpeas from a Turkish shop (leblebi), believe me, they are one of the yummiest goodness snacks I ever ate (they come with and without salt). I feel pretty loaded with them, would dare to say more than with nuts.