Daniel 1:12-15

“Please test your servants for ten days, and let them give us vegetables to eat and water to drink. Then let our appearance be examined before you, and the appearance of the young men who eat the portion of the king’s delicacies; and as you see fit, so deal with your servants.” So he consented with them in this matter, and tested them ten days. And at the end of ten days their features appeared better and fatter in flesh than all the young men who ate the portion of the king’s delicacies.