All good thoughts.

Presuming you have some way of melting snow and boiling water, dehydrated food might be the way to go.

Personally, I always like crackers and PB or pate - I can get little tins and spread on a cracker it gives me carbs, fat and protein.

Key point - if you are looking for a little boost at the end of a long day, make sure you pack what YOU like - nothing worse than getting to the end of a hard day and having to eat something you don't like.