An orange will give you quick energy right now and vitamin C for later. A pile of potato chips, on the other hand, contains lots of calories and fat, something that most kids don't need a lot of. Some foods, such as whole-grain foods, also will help you feel more full for longer. So a whole-grain muffin will stick with you longer than a candy bar. It's also easy to over eat candy or chips and they contain a lot of calories.