Xerophagy, meaning “dry eating” in Greek, is the practice of eating uncooked foods, such as raw vegetables, fruits, nuts, and grains.
To eat this way was considered “dry” because so much of ancient fare was cooked using rich-tasting olive oil for flavoring.
Xerophagy is a form of fasting commonly observed during Great Lent and at other fasting periods of the Church.
Today, however, it has also come to include cooked vegetables (boiled or roasted without oil) and breads.Fr. John Archangel Michael Orthodox Church
In addition to the above, on the days when xerophagy is prescribed one meal for the day is intended.