Looking back, I think most parents fall into two categories with each child:

1) S/he does NOTHING but eat!!!!!
2) S/he doesn't eat enough!!!!

I assure you, if he's gaining weight, he's fine. And if he's breastfeeding still, doubly so.

As 2gifts recommended, he's also testing his limits. Set them and enforce them. Food isn't a toy, if he's insisting on treating it as such, remove it.

Also, for things that are only good for bowls, they make suction-cup bowls that suction to the high chair or table, and will, if not eliminate the dumping (he can still fling!!!) at least cut down on it.

GSF