The family goes to the library's used book sale, where Marge manages to entice the normally book-hating Homer into buying a copy of Duff's Book of World Records. When Homer goes through all of the records, he plans to set one of his own. Duff tells him that all the personal records have been set, and that he needs to help set a group record. Homer then persuades the town to try to set a record for the world's tallest human pyramid, and with Maggie's help, the world's tallest human pyramid is set. However, everyone has to stay put for "three Mississippis" for the record to count. After two Mississippis pass, Jimbo and Kearney’s hands touch, and they pull them back in revulsion causing the entire town of people to collapse and form a giant ball. The ball rolls down a steep hill (inadvertently saving a man trying to commit suicide) and land on a truck depot scale, where the officials, after doing some calculation (based on the number of people, subtracting belts and shoes), declare Springfield the world’s fattest town.
The town is soon celebrating its collective obesity, but Marge is the only person that has a problem with it. She goes to the Motherloving Sugar Company to lodge her complaint after she finds out that every single food sold in the town is packed with sugar. The owner, Garth Motherloving, is less than cooperative, so Marge files a class action lawsuit. Professor Frink blows the whistle on "big sugar" and the court rules in Marge's favor and then bans all sugar from Springfield forever (which first makes Homer hug Marge at court, but later in court he finally understands what it is, and he says, "Get in the car" in his non-loud angry voice). All the town's sugar products are burned and Apu's store shelves are empty. Apu brings Homer into a group determined to smuggle sugar back into Springfield. Homer and Bart join with Apu, Mr. Burns, Count Fudgula and Garth Motherlovering in a scheme to smuggle in sugar from the island of San Glucose. They get the sugar (for free since the smugglers forgot to ask for any money in their contract) and make it into Springfield Harbor, but are intercepted by the police. Evading Wiggum and Co., Homer finds himself faced with the decision to either "Dump Cargo" to make Marge happy or "Obey Bad Guy" and bring sugar into Springfield. He chooses the former, dumping all of the sugar into the ocean. The town soon realizes his action and takes advantage of the opportunity by jumping into the ocean and drinking the sugary water. Judge Snyder then realizes that he has overstepped his authority and once again makes sugar legal in Springfield.