sleep eater
A person who engages in somnambulistic eating, often ingesting large quantities of food rapidly and without restraint. Sleep eaters are known to be indiscriminate in their selection, combining foods both hot and cold, dishes spoiled or rotten, and substances that are toxic or even life-threatening. Further injury may occur from the careless preparation or acquisition of food items (cutting meat with a knife; removing goods from a stove, oven, or boiling pot; or opening a can or other container).
Randy is a hopeless sleep eater, rising from bed as if rising from the dead, night after night, gorging himself on all the pantry can hold.