While growing up there would be a chart of a human body that says that we are what we eat.  It is said that we are a reflection of what we believe.  It is also said that the things that we believe in are the things that we do.  Romans 7 says that the things that the spiritual nature hates, our sinful nature does.  So, how do we overcome the sinful nature that causes us to do what we say we do not believe in?  We must feed our minds the Word of God, so that we fill up on the things that His Word declares, therefore, strengthening our inner self when we decide what we do.