Prohibited foods were unwholesome, and injurious physical habits corrupt spiritual capacity.

Original passage

Many articles of food eaten freely by the heathen about them were forbidden to the Israelites. It was no arbitrary distinction that was made. The things prohibited were unwholesome. And the fact that they were pronounced unclean taught the lesson that the use of injurious foods is defiling. That which corrupts the body tends to corrupt the soul. It unfits the user for communion with God, unfits him for high and holy service.