This is one thing that is mind boggling, Why won't my son finish a meal? He does on occasion finish a meal but for the most part he has to leave one part or piece on his plate, leave the room and then proclaim he needs a snack. This even goes on when it is food that would be considered his favorites, i.e. Peanut butter and Jelly, Wendy's, or cheese. I thought at first maybe he is saving it for later, but to this day he has yet to come back and finish any meal that is left behind. Yes he snacks some between meals but we do not over do it and I try to set limits on when he will get a snack for the sake of meal times. Maybe the answer is to just start calling all meals snacks and call snacks meals. He is not old enough yet to understand the comment, "There are starving kids in the world that would love to eat that." For being a little over 3 years old and just over 41 inches tall you would think he would eat anything he gets his hands on, maybe he gets take-out delivered when we are sleeping as evidence will show there is a lot of stink when he calls out those words that wake us up in the morning.
TIP: I have found using an ordinary pizza cutter works wonders for cutting all types of sanwiches for kids into small squares or triangles, and even trimming the crust. The sandwich doesn't get smushed or torn into bits while trying to use a knife, plus it is very quick.