Many thought that Jesus was speaking of cannibalism, but He was speaking of the spiritual man.  Just as the physical man receives life from the food he eats,  the spiritual man receives life as he partakes of Jesus, the life of men (John 1:4; 10:10; 14:6) or the "Bread of Life."  Just as the life of a root is found in the soil, or a branch in the vine, or a fish in the sea,  the believer's true life is found to be in joined with Christ.

The Bible presents salvation as a life transforming experience.  Change is one of the characteristics of a true believer.   Failure to understand that this change takes place in the spirit first, and is then reflected in the outward thoughts and actions, depending on the way we renew our minds.  This causes much confusion.  This change has to take place in our bornagain spirit.   Our body doesn't instantly change.  Our soulish or mental realm doesn't instantly change. 

How we think about things before we got saved will be how we think after we get saved, until we start renewing you mind.  The only part of us that is left is our spirit.  It is our spirit that is instantly changed at salvation.  It is perfect (Hebrews 12:23).  It cannot sin (1 John 3:9).  Everything that is true of Jesus is true of our bornagain spirit.  Our spiritual salvation is complete. 

 At salvation, we receive the same spirit that we will have throughout all eternity.  It will not have to be changed again or cleansed again.  It has been sealed with the Holy Spirit (Ephesians 1:13) and is therefore sanctified and perfected forever (Hebrews 10:10, 14; 12:23).  Jesus lives in the spirit of believers.  All that He is will be available to us if we will depend on Him instead of your own abilities.