Protein is in nuts, cheese, peanut butter, yogurt, lots of stuff you wouldn't necessarily think of. Celery and peanut butter with raisins (ants on a log?) carrot sticks cucumber slices grapes (can be a choking hazard depending on age) raw broccoli and cauliflower sunflower seeds and a bunch of other stuff has made its way into our ice trays. Cheese cubes or pepperoni slices or yogurt in some of the slots if you keep it refrigerated.

Good luck!!