A human being is consisted of three parts: mind, body and soul. We are naturally predisposed to follow our body's instincts. That is why things such as eating and sleeping are so easy to do. However, from the word of God, we learn that we are meant to be led by the Spirit of God.
Rom. 8:14 [NKJV]
ForĀ as many as are led by the Spirit of God, these are sons of God.
Therefore, a large part of our work as Christians is training ourselves to listen to our spirit rather than our bodies.