Those who skip lunch have lower levels of concentration in the classroom during the afternoon. The ideal school lunch contains sandwiches, rolls or pita bread with a healthy filling, plus fruit. Water is usually available at school or you can pack a bottle of frozen water.
Fruit juice is suitable also.
During growth spurts, children are hungry and may need a larger lunch. The best idea is for them to have more sandwiches and fruit. Don't forget to include different types of rolls sometimes, or use pita, lavash or flat breads rolled around fillings. You can also use two different types of bread - for example one slice of white, one slice of wholemeal. In winter, a thermos flask of soup is warming.