Thomas Merton wrote:

No one who simply eats or drinks when he feels like eating or drinking or smokes whenever he feels the urge to light a cigarette, or gratifies his curiosity and sensuality whenever they are stimulated, can consider himself a free person. He has renounced his spiritual freedom and become the servant of bodily impulse. Therefore his mind and his will are not fully his own. They are under the power of his appetites, and through the medium of his appetites they are under the control of those who gratify his appetites.