At the end of the day, if they don’t starve or get scurvy, you’re doing fine.
Make a big batch of PB&J sandwiches in advance and freeze them.
A great idea from Money-Saving Mom: These will keep just fine for about 4-6 weeks. Just take one out of the freezer in the morning, pack it, and it will be thawed and ready to go by lunch time.
You can also freeze individual portions of rice or pasta and reheat them before you pack lunch.
Get the full instructions at Momables.
Put a rubber band around a sliced apple to keep it from turning brown.
Alternatively: Don't slice the apple. But this trick is pretty neat!