Similar to voodoos suggestion but I make large quantities of fruit salad to snack on (more interesting than just eating apples). Usually mangos, kiwis, pears, grapes, mandarin oranges and bananas, the whole bowl is about 400kcal but its a very large bowl and usually takes me the whole day to get through it.
Wooster, was it you who asked before about veggie alternatives to jelly babies. If not I think someone said that joosters were a good alternative.