You can try some of the dehydrated fruits (pineapples, peaches, raisins, apples, figs). Check out your local sporting/camping stores for backpacking foods. Usually pasta based, but they have side dishes, desserts, breakfasts too. Usually these are vacuum packed, and need water to reconstitute.

As for your drinks, can you have stuff like Kool-aid or lemonade powders, to vary the taste?