Just feed dinner as "snacks".

Kids eat when they’re hungry or thirsty, sometimes not realizing there’s a difference. Kids can have a drink of water then go back to playing. If they come back for a snack within 20 minutes, they’re actually hungry and they can have a reasonable, healthy snack.

As some others have said, I don’t care about unlimited snacking as long as it’s healthy. If my son is hungry, he can always have grapes, carrot, apples or pretzels (or any other fruit/veggie in the house.) there is a limit on the junky snacks, like chips and sweets. He stills gets 1-2 of those daily.