An altered physical appetite is a sign of changes in the body and an altered spiritual appetite is a sign of a work of God in a man's heart. People that are blessed by God have a hunger and thirst after righteousness. In this case "righteousness" is referring to a desire to be right with God. This is not the appetite of men and women apart from the grace of God. When a man has an appetite to be right with God, the longings of his heart will be satisfied by God himself.