"Bread and water" refers to the most basic of meals. It is a common policy to give prisoners only what is necessary to survive and nothing more. In 2375, while imprisoned in USS Voyager's brig for thirty days, Tom Paris referred to Captain Kathryn Janeway's orders that he be given "basic nutrition only" (in this case, leola root stew) as "bread and water". (VOY: "Thirty Days")