The first experiment is about college aged males and therefore not directly applicable to children though I suspect it wouldn't be an outrageous leap to apply it's findings to children.

The second experiment though is about having confectionary snacks or nothing for breakfast. All it suggests is that having some calories is better than no calories, it doesn't compare having a healthy snack vs a non-healthy one.

The reality is that there are too many contradictory studies regarding nutrition, especially children's nutrition. For every advocate for a particular health advice, you'll find 3 people who argue that it's terrible for you.