Nuts are very high in nutrition, fiber and fat. Therefore they will make you full pretty fast on very little weight to carry. You dont want to carry around too much weight when hitchhiking: See my posts about travelling light!
Other fruit or vegetables if I fancy or have access to at the moment:
-Apples: stays fresh pretty long and are high in nutrition
-Cucumber: stays fresh fairly long and fills your stomach soon. Also good: Zucchini
-Salad: its a bit of a hassle because you need to rinse it beforehand but it does not take much weight
-Bananas. The problem with those is that they get squeezed in the bag and they are heavy to carry. Salad is easy to carry and not heavy either.
-Carrots: excellent travel food, stay fresh for a long time and is easy to eat along the way.
Possibly other foods you wish to give to the drivers as a gift.
--> BUT most important: Have a good breakfast before you head off :)
WATER:I only carry a small bottle which I fill up at every possibility. That was I always have enough water inside my body. It is not necessary to drink that much, if you are in a colder country and if you eat lots of vegetables. They hold the water inside your body :)
Good travels my dear friends. Let me know if you need more advice!
Getting hungry? See my recipe blog here!