Buy sosmix and burgamix. These are already dried, contain fat and they are excellent for adding extras to. Take dried potatoes and you have sausage and mash. Birds sell instant custard, add hot water and stir in some chopped dried apples or apricots and you have pudding.
All of these can be high in calories, and are filling, comfort foods, but still very light and relatively cheap. However one can get very tired of dried food. There are jars of dried, fried onions available for sprinking through salads, these are tasty through potatos/couscous/quinoa or mashed spuds and weigh very little. High in calories though. My bother (sorry, brother
) takes little tins of oily fish like mackeral; he claims it's tasty, rich in protein and calories too. Chinese supermarkets sell these dried and sealed in plastic so they weigh next to nothing and they're cheap. I noticed yesterday that they have dried pork and chicken too.
Personally, as a vegetarian, I always carry lots of nuts and I like Quinoa which is a complete protein in it's own right. Cashew nuts and almonds are both excellent to cook with. Things like cereals are still tasty, so's popcorn and a few grains can go along way and it cooks quickly on a fire or stove. I like oats and muesli too for munchies.
I find I always dry too much food and the compost heaps get regular donations, I can't offer meat, but I do have extra mushrooms if you'd like them.
Best of luck with it all,
Cheers,
Toddy