It is quite easy to become a slave to the body.  You are trained to respond to its demands.  You feel the slightest twinge of hunger, and you eat.  You feel the slightest dry mouth, and you drink.  A bit of pain, and you take an aspirin.  There is nothing wrong with these behaviors, but they do keep you acting a bit like a robot, responding instead of pausing to step beyond the body and be present.  Ah, there is hunger.  Yes, I notice thirst.  Ah, there is a headache.  Why is this important?  For when you next experience fear, anger, guilt, or other such discomfort, and you practice presence, you may well pause and examine the root cause instead of running away or stuffing it down.  Do this, and the prisoner will finally be free of the shackles.  You are so very loved.