I think finger food is the best. Food that doesn't need knives, forks, or spoons. There should be a good balance of all the food groups. Think of a packed lunch as a miniature. Start with your main - these could be sandwiches with a selection of fillings such as cheese, ham, and cucumber, which gets in your proteins and vegetables. With all the variety of fillings available, they can have something different everyday. Occasionally you could treat them to something that might not be quite so healthy, like sausage rolls or party eggs. For their sweet treat apples and bananas are a great healthy snack, but you can also give them dried fruit like a packet of raisins, dates, or figs. Every now and then you can treat them to a packet of crisps.