J.B.
milk is easy-
cut back the milk to a max of 16oz a day.
offer food on a schedule.
if the issue is "play play play", set up a snack station in the kitchen.
he will eventually get hungry.
kids have a hard time telling the difference between hunger and thirst and they all start out on liquid diets. it's hard to force the transition to solids- but it's important.
also- sometimes all a kid knows to ask for is milk.
offer a plate with a variety of things- cheese, soft veggies, boiled egg, crackers, fruit pieces etc.. if he picks at it or barely eats- don't sweat it. kids in America seldom starve by choice. I feed my kids on a schedule and they know when to expect food - so they're hungry at meal and snack times. Remember when he starts school he'll have to eat on a schedule. also- maybe try giving him choices about his food for meals like lunch or dinner. it helps!
Good luck!