Tip number 1: avoid tin cans and glass jars. Go for powdered/dried ingredients as much as possible. Pouches of cooked protein (tuna, chicken) is fine.
Tip number 2: spices/seasoning. The right spices turns "ingredients mixed together" into a proper dish.
Tip number 3: Start saving/buying goods in small bottles or other (sealable) containers. Get a couple of sturdy ziploc bags. You don't need to carry a big glass bottle of olive oil, just pour what you need into a tiny bottle. Don't bring whole packets of pasta, take what you need in a ziploc. I bought super-cheap plastic test tubes with stoppers on Amazon to put spices in.
Breakfast: oatmeal, raisins, nuts, powdered milk. Mix with hot water. A couple of crackers/cookies and a cup of tea (put teabag in water).
Snacks: Home made trail mix. Buy peanuts, nuts, dried fruits, raisins, candied ginger, M&M:s, whatever you like. Mix in a bag. Also, cereal bars, or candy bars.
Lunch: Something which doesn't require cooking. Usually peanut butter sandwiches and trail mix. You can mix it up a little (e.g. tortilla bread, Nutella, banana chips). Cured meats (salami, fried ham) and hard cheeses also go well with bread. I wish my country had chicken/tuna pouches, or tetra packs with cooked beans. Cold soaking couscous (mix with water in the morning, by lunch time it's soft and edible) and mixing with cashew nuts and maybe some olive oil and dried onion could be nice.
Dinner: Break out the stove and boil your water. Carbs: instant pasta/ramen/mash/couscous/polenta/rice. Protein: cured meats, chicken/tuna pockets, freeze-dried beans, cheese, dried bacon bits, dried fish, shrimp or mushrooms, onions curls. Add flavor with spices or sauce powders.
Some recipes: Instant mash, mix with dried grated Parmesan, eat with salami.
Instant noodles, cook with dried mushrooms or sundried tomatoes. Drain, sprinkle with Parmesan.
Dried shrimp, cook with instant rice. Drain most water, mix with coconut milk powder and curry powder.
