The book of Daniel chapter 1 from verses 5 through 16
In the various versions of the old testament of the Bible we read in the book of Daniel of the foods of fruits and vegetables and the purifying effects of water both to cleanse and to drink. These chapters tell the story of a king who offered a group of men training to be in his service a portion of the wine and food from his own table.
One of these men, Daniel, preferred not to partake of rich and fattening foods and beverages, and stated that such rich and indulgent foods would have a negative effect on his health and vigor.
He asked for a ten days comparison test in which one group would indulge the finer foods and wines and other group would eat only fresh vegetables and drink only water.
After the ten days, those who partook only of water and vegetables were better nourished and healthier than those who consumed the richer foods from the royal table.