The Eucharist was allegedly instituted by whom ?
( Catechism of the Catholic Church 1323 ) Eucharist in the Catholic Church refers to both the celebration of the Mass , that is , the Eucharist liturgy , and the bread and wine which after the consecration are transubstantiated ( changed in substance ) into the body and blood of Jesus Christ , Lord and God , a declaration formulated by the Council of Trent with an anathema against anyone who denied this .