Again in today's Gospel reading at Mass, John 6.52-59, Jesus spoke clearly: "Amen, amen, I say to you, unless you eat the Flesh of the Son of Man and drink his Blood, you do not have life within you." He emphasized this several times more in this passage. Try adding the word "symbolically" after "Man" and Blood" and reread the whole sentence. You'll see that the word "symbolically" is totally out of place.
Jesus fulfilled his promise by instituting the Holy Eucharist later at the Last Supper.