Catechism of the Catholic Church
“What material food produces in our bodily life, Holy Communion wonderfully achieves in our spiritual life. Communion with the flesh of the risen Christ, a flesh ‘given life and giving life through the Holy Spirit,’ preserves, increases, and renews the life of grace received at Baptism. This growth in Christian life needs the nourishment of Eucharistic Communion, the bread for our pilgrimage until the moment of death, when it will be given to us as viaticum.”
Source: Catechism of the Catholic Church #1392