In the Jewish tradition the manna in the desert was associated with the giving of the Torah, and the wisdom of God is often portrayed by the metaphor of food.  While speaking of the bread of life, Jesus use language of believing, drawing near, and listening, terms associated more with assimilation of wisdom than eating.  Full participation in eating the body drinking the blood of Jesus follows upon personal commitment and love which draws a person to absorb the teaching of Jesus and imitate his life given for others.