Lunch
Other possibilities
Chips (for sparkle) - if that's all you eat, you will run out of energy
Suggestions
Things you can eat without cooking...
Bread/ cheese / salami sandwiches
Crackers and cheese and salami
Apple or other hard fruit
One square meal (2 bars = 1 square = whole meal)
Hard boiled egg
Tuna/ chicken and crackers (if you want to carry tins)
Bread and banana (watch out for squishiness in your pack)
Energy bar
Biltong and crackers