Daniel 1:11-14

11Daniel then said to the guard whom the chief official had appointed over Daniel, Hananiah, Mishael and Azariah, 12“Please test your servants for ten days: Give us nothing but vegetables to eat and water to drink. 13Then compare our appearance with that of the young men who eat the royal food, and treat your servants in accordance with what you see.”

14So he agreed to this and tested them for ten days.