Daniel 1:12-15 NIV
“Please test your servants for ten days: Give us nothing but vegetables to eat and water to drink. Then compare our appearance with that of the young men who eat the royal food, and treat your servants in accordance with what you see.” So he agreed to this and tested them for ten days.
At the end of the ten days they looked healthier and better nourished than any of the young men who ate the royal food.
NIV: New International Version