While exercising with Libby, Hurley tells her the reason he can't lose weight is because he's "sick." His sickness, he explains, is compulsive eating. We learn through Hurley's flashback that Hurley blames himself and his weight for the accidental deaths of two people. He stepped onto a deck that was already dangerously overloaded, and it collapsed, killing the aforementioned two individuals. Due to the guilt he felt, Hurley became "practically catatonic," and his mother instiutionalized him at Santa Rosa. There, Hurley resists changing, and dealing with his feelings about the accident. He punishes himself by creating an imaginary friend "Dave" who encourages him to continue eating.