Buckwheat

Buckwheat is one of those rare foods that I can eat day after day without getting tired of it. It is a bit of an acquired taste, and I ate it for years in Ukraine and Russia. Buckwheat sold in the U.S. is generally of a lower quality and turns to mush when boiled, so I recommend heading down to the nearest Russian foods store to buy the real thing. A bag of 1 kg of dark brown buckwheat groats imported from Ukraine or Russia ("grechka" in Russian) should cost between $2 and $3. 

Buckwheat is not a grain like many people think. It provides a high amount of complete protein (13 grams per 100 grams) that's supposedly better than that of soy or even fish and packs over 300 calories per 100 grams. At $2.50 for a kilo, that's a really good deal on a prime protein source. I personally just boil it and eat it with butter and vegetables, cheese, meat, or beans. 

Buckwheat takes about 10 minutes in boiling water to cook. You can also soak it in warmish water for half a day and just bring it to a boil, and it'll be ready. 

I'm considering making buckwheat a staple for my hike and eating between 150 and 200 grams a day for lunch or dinner. That's 20 grams of protein and lots of complex carbohydrates.