Cut some boneless skinless chicken breasts into strips and bake it.(I spray the tops of them lightly with pam before I bake so they don't dry out) then store them in the freezer(doublewrapped) and microwave them quickly when needed. Protien helps keeps bellies saistfied, grains, newtons and crackers can tend to trigger more hunger because they increase blood sugar.
Spread some refried beans(protien) on a tortilla and roll it up ,cut it into pieces. These can also be made ahead and stored uncut, again double wrapping, (wrap once in tight saran, then put them in a ziploc, Filling the bag so there is not alot of air space but not too tightly.)
Cut a bunch of washed (but unpeeled- keep those vitamins) carrots into sticks and put them into a cup of water and put them in the fridge (I don't buy pre cut carrots because of the processing chemicals on them, the chemicals in the bag they are in, and mini carrots I've read are really big carrots, peeled and pared down to take off rot and blemishes and resold.)
put out ranch dip.
sugar beans and peas also can be eaten raw and some kids love them.
These are not as healthy but it's an idea: spray a muffin tin with pam. Put a half of a refrigerator biscuit in each, pressing in to form a well and sides. fill with goodies, like scrambled eggs and cheese, sanusage, etc (makes a mini quiche.) These are good to make ahead also.
I do my make ahead on Sunday and use them within the week or two. If they stay in the freezer a long time they can get nasty from freezerburn.