I would say they all have phases of playing with or dropping food. I would serve less, so one bit on his tray and the rest out of reach on a plate then once he has eaten what is on his tray he can have more, it just reduces the amount that can be thrown. Or, as you have done end the meal. When I ended a meal early I would try to keep it light hearted and just say "okay you aren't hungry, let's finish" and I might give him one chance to come back if he changed his mind but I wouldn't have him coming to and from the meal repeatedly, it's either eat or don't. He can always make up for it at the next meal.
Appetites tend to drop at around 12 months so this may be part of it although your LO is only 11 months. Teething can also have a big effect. I would try to stay calm and not worry but avoid too much of a habit of the dropping by not letting it happen.
Your LO might also like to play some fill and dump games so perhaps you can set him up in A time with some dry pasta and cups so he can pour and fill.