My rations for hunting trips are composed mostly of high fat/protein foods (pemmican, salami, nut butters, etc.) with a few scoops of protein powder to get my macros to the desired ratio.
Protein generally has the lowest caloric density of the three macros, but given the choices for adding protein without additional carbs or fat, protein powder would appear to be the best option (100 kcal/oz vs. 73 kcal/oz for lean jerky).
I'm getting 3933 kcal out of my current ration at ~31 oz, so about 126 kcal/oz. With that, I get 206 g protein, 222 g carbs and 247 g fat, so about 21/23/56.
As far as how to consume it, I prefer to drink it. My appetite tends to decrease at altitude, so calories easily consumed and digested are calories actually eaten and not left in the bag. Those qualities are also useful during the long stretches when you have to eat, but don't want to stop.