Daniel 1:11-17

Then Daniel said to the steward whom the chief of the eunuchs had assigned over Daniel, Hananiah, Mishael, and Azariah, “Test your servants for ten days; let us be given vegetables to eat and water to drink. Then let our appearance and the appearance of the youths who eat the king’s food be observed by you, and deal with your servants according to what you see.” So he listened to them in this matter, and tested them for ten days. At the end of ten days it was seen that they were better in appearance and fatter in flesh than all the youths who ate the king’s food. So the steward took away their food and the wine they were to drink, and gave them vegetables. As for these four youths, God gave them learning and skill in all literature and wisdom, and Daniel had understanding in all visions and dreams.