"Fat Kid Rules the World" is a young adult novel by KL Going that follows the story of a teenager named Kevin. Struggling with obesity and bullying, Kevin feels isolated and unsure of his place in the world. His life takes a turn when he meets Mack, a talented but troubled musician who encourages him to embrace his individuality and pursue his passion for music. As their friendship develops, Kevin gains confidence and learns to navigate the challenges of adolescence. The novel explores themes of friendship, self-acceptance, and the importance of following one's dreams, all while addressing the complexities of growing up in a judgmental society.