Do Catholics really believe the Eucharist is the Body and Blood of Jesus?

Yes, literally. The Church teaches that at the consecration the whole substance of the bread becomes the Body of Christ and the whole substance of the wine becomes His Blood, while the appearances (taste, color, texture) remain. The word for this is transubstantiation (CCC 1373-1381; Council of Trent, Session XIII).

Jesus said so, and refused to soften it. In John 6 He says: "My flesh is true food, and my blood is true drink" (Jn 6:55). When listeners objected, He did not say "I meant it symbolically." He repeated it more graphically, using the verb trogein, "to gnaw." Many disciples left over it (Jn 6:66), and He let them go. At the Last Supper He said, "This is my body ... this is my blood" (Mt 26:26-28), and St. Paul warns that whoever eats unworthily "will have to answer for the body and blood of the Lord" (1 Cor 11:27-29), a strange warning if it were only bread.

The early Church believed it unanimously. St. Ignatius of Antioch (c. 107) condemned those who "do not confess that the Eucharist is the flesh of our Savior Jesus Christ." St. Justin Martyr (c. 150) wrote that the food "is the flesh and blood of that Jesus who was made flesh." No Christian writer for the first thousand years taught a merely symbolic view.

What it means for you. Because Christ is present, Catholics genuflect, keep the Blessed Sacrament in a tabernacle, adore Him in Eucharistic adoration, and must be in a state of grace to receive (CCC 1385-1387). The Eucharist is "the source and summit of the Christian life" (Lumen Gentium 11; CCC 1324). It is not a reminder of Jesus. It is Jesus.