Under extensive medical supervision, Spurlock subjects himself to a steady diet of McDonald's cuisine for 30 days just to see what happens. In less than a week, his ordinarily fit body and equilibrium undergo dark and ugly changes: Spurlock grows fat, his cholesterol rockets north, his organs take a beating, and he becomes subject to headaches, mood swings, symptoms of addiction, and lessened sexual energy. The gimmick is too obvious to sustain a feature documentary; Spurlock actually spends most of the film probing insidious ways that fast food companies worm their way into school lunchrooms and the hearts of young children who spend hours in McDonald's playrooms. French fries never looked more nauseating.