Like all meals, this dinner started with some preparations. The prodigal son didn't go from dining with his father one day to eating with pigs the next. There was a transition, and it started with discontentment. He was not satisfied with what his father was providing for him.
The prodigal son's father gave him what he needed to go start life out on his own. He was not content with his father and wanted to live his life his own way. He went out and wasted everything that his father had given him. It wasn't long until he had nothing left. He lived life his way, and it lead to the pig pen.
The prodigal son wasted everything that his father had given him. He didn't plan or prepare for hard times, and when they came he had nothing left. He started out dining with his father, but now he is having dinner with pigs. He finally hits rock bottom and wants to get out. It's time to back away from the table and go back home.