All pizza is high in fat (especially the saturated kind) because it's loaded with cheese, but that's only part of the problem. Pizza simply doesn't contain a whole lot of nutrients. There's plenty of fat, sodium and carbohydrates; and while some school boards consider pizza sauce to be a vegetable, most health experts beg to differ.
Still, it gets worse. Pizza topped with pepperoni leads the list of slices you probably don't want your child eating for lunch. Pepperoni adds even more fat, and evidence has shown that eating a lot of cured meats (and processed meats in general, in fact) may contribute to increased cancer risk.