As I understand it, the traditional Jewish practice for fasting which our tradition comes out of was to fast from sunrise to sunset, only taking food after the sun went down.
Abstaining from select foods vs. total abstinence is also attested both in Judaism and early Christianity; forgive me for providing just a few select examples...
"On some occasions, the fast was not a total one, but people refrained only from meat, wine, anointment with oil, and other pleasures (Cowley, Aramaic, no. 30; Dan. 10:3; Test. Patr., Reu. 1:10; Judah 15:4; iv Ezra 9:24; as well as generally in talmudic literature and in that of the Middle Ages)." "Jewish Holidays: Fasting & Fast DaysEncyclopaedia Judaica (2008) https://www.jewishvirtuallibrary.org/jsource/Judaism/fasting.html
Tertullian regarded the prohibition not to eat of the tree of the knowledge of good and evil to be the first commanded fast; Jewish Kosher laws also constituted a sort of fast. De jejunio (or De ieiunio), "On Fasting" (c. 208 AD). "According to Tertullian, God allowed a widening of allowable foods after the flood, because man had proven himself unable to keep even the lightest commands. The law of Moses then restricted more food usage, as God revealed to his people, whom he was restoring, more of the nature of their need for abstinence... As evidence for xerophagies, he cites Daniel and his friends abstaining from wine, as well as Paul’s instruction to Timothy to take a little wine for his stomach (1 Tim 5:23)" https://bible.org/seriespage/chapter-3-fasting-through-patristic-era
Shepherd of Hermas/Book III Simultude V Chapter III "in the day on which you fast you will taste nothing but bread and water; and having reckoned up the price of the dishes of that day which you intended to have eaten, you will give it to a widow, or an orphan, or to some person in want, and thus you will exhibit humility of mind, so that he who has received benefit from your humility may fill his own soul, and pray for you to the Lord. If you observe fasting, as I have commanded you, your sacrifice will be acceptable to God."
St. Basil, About Fasting, Sermons 1 and 2 "Basil requires complete abstinence from all that is harmful, but as food needs differ from person to person, much latitude is allowed. But the stomach should not be full, and eating should be for necessity and not for pleasure. Monks should eat as little as possible to get by, and be satisfied with water to drink (Longer Rules 19)... Unfortunately they are not readily available in English, and so a fresh translation has been undertaken, and can be found in the appendix. These English translations will be referred to as About Fasting 1 and 2. " “Fasting is as old as mankind itself. It was given as a law in paradise. The first commandment Adam received was: ‘From the tree of the knowledge of good and evil do not eat.’ Now this command, ‘do not eat,’ is the divine law of fasting and temperance.”352 Abstaining from the tree of the knowledge of good and evil was a command to Adam and Eve to fast, before sin ever entered the human race. Humanity could have been like the angels, partakers of divinity. But with their failure to keep the appointed fast came the curse of pain and toil, and Basil quips: “If Eve had fasted from the tree, we would not have to keep this fast now.353 Biblical Examples of Fasting. Basil engages a good deal in what Musurillo referred to as citing “exempla,” characters from sacred history that are used to illustrate the desired fasting principles, positively or negatively.356 Noah, although he got drunk, is excused, because he was ignorant of the potency of wine, and after the great flood man’s food regimen was altered away from the ideals of paradise. Moses fasted forty days and received the divine law, but it was for naught, as the people ruined the results of this fast with one night of drunken debauchery.357 Esau threw away his birthright for a single meal, the glutton! By contrast, Hannah conceived the prophet Samuel because of fasting. Likewise Samson’s parents conceived him in fasting, and he was nurtured to manhood and great strength through fasting regimens of the Nazirites. Elijah received his beatific vision of God after fasting, and he and Elisha performed great exploits related to their fasting and austere lifestyles. The three Hebrew children escaped the fiery furnace because fasting had turned their bodies into inflammable substances.358 Likewise, lions could not eat Daniel, because they “weren’t able to sink their teeth into him. Fasting is like sharpening the edges of a man by dipping his body in iron—it makes him tougher than lions! They couldn’t open their mouths against the saint.” So “when he was thrown down in their den, he taught the lions to fast!”359 -op cit https://bible.org/seriespage/chapter-3-fasting-through-patristic-era
An example of reduction from select vs. total abstinence from the Apostolic Constitutions:
"Do you therefore fast on the days of the passover, beginning from the second day of the week until the preparation, and the Sabbath, six days, making use of only bread, and salt, and herbs, and water for your drink; but do you abstain on these days from wine and flesh, for they are days of lamentation and not of feasting.... Therefore, after you have kept the festival of Pentecost, keep one week more festival, and after that fast; for it is reasonable to rejoice for the gift of God, and to fast after that relaxation: for both Moses and Elijah fasted forty days, and Daniel for "three weeks of days did not eat desirable bread, and flesh and wine did not enter into his mouth." And blessed Hannah, when she asked for Samuel, said: "I have not drunk wine nor strong drink, and I pour out my soul before the Lord." 1 Samuel 1:15 And the Ninevites, when they fasted three days and three nights, Jonah 3:5 escaped the execution of wrath. And Esther, and Mordecai, and Judith, by fasting, escaped the insurrection of the ungodly Holofernes and Haman. And David says: "My knees are weak through fasting, and my flesh fails for want of oil." -Apostolic Constitutions http://www.newadvent.org/fathers/07155.htm