Chocolate Rules & The Starship Meatloaf — Jerry Piasecki

In this companion novel to Ketchup Power and the Starship Meatloaf, the Starship crew and their four sixth-grade visitors travel to the future of 6789. However, two stowaways are on board, and the future has never seen anything quite like Bertha and Beula Butterman, the evil lunchroom ladies. When the Buttermans discover that people in the future have never tasted chocolate before, the two lunchroom ladies decide to introduce the confection to them. Soon everyone on Earth is hooked on all things chocolate and will do anything the Buttermans say to get more. It is left up to four time-traveling sixth graders and their friends to overthrow the chocolate queens and return the world to its pre-chocoholic state.