From A Biblical Walk through the Mass: Understanding What We Say and Do in the Liturgy by Dr. Edward Sri, provost and professor of theology and Scripture at the Augustine University, in regards to the Our Father:
Give us this day our daily bread: …in the Bible, bread is the most basic kind of food and was viewed as necessary to sustain life. Mention of bread did not bring to mind simply food or nourishment; it was also a symbol for support of life in general. The mention of “daily bread” in this petition refers to our daily needs. In particular, it recalls the daily manna given to sustain Israel in the desert (Ex 16:16-22). Just as God gave each person exactly the amount of heavenly bread they needed each day, so he continues to provide for our needs each day today. Finally, this petition also has Eucharistic overtones as the prayer for daily bread points to the Bread of Life we are about to receive in holy communion.