We have seen this too often where kids and adults continue to clean up all the food on their plate even when they are full and stuffed like Thanksgiving turkeys. It is absolutely okay to eat half a plate, and put the rest into the fridge.
Imagine yourself going to a restaurant, and the dishes of food that comes out from the kitchen are huge portions. You have to make a choice whether to doggy bag the remaining portions or finish the plate.
The smart choice is doggy bagging it for next time. Just because you don’t finish your serving does not mean you are wasting food.
Retrain yourself. You don’t have to finish the french fries, the last chicken wing, or the extra bite of dessert.
Save it for next time. Let your body have some time to burn off the fuel before feeding it more food.