Sherman Klump is a college professor who is kind, has a good heart and is overweight. He meets an admirer of his work named Carla and becomes infatuated with her but becomes frustrated because of his weight. He decides to change his DNA and he then becomes a fast talking swinger named Buddy Love. After a while Buddy decides he is there to stay and Sherman must decide if he has the courage to be his true self and tell Carla how he really feels or disappear and let Buddy live the life he never had a chance to live.