The film depicts an experiment he conducted in 2003, in which he ate three McDonald's meals a day every day (and nothing else) for 30 days. The film's title derives from one of the rules of Spurlock's experiment: he would not refuse the "super-size" option whenever it was offered to him but would never ask for it himself. The result, according to Spurlock, was a diet with twice the calories recommended by the USDA. Further, Spurlock attempted to curtail his physical activity to better match the exercise habits of the average American (he previously walked about 3 miles a day, whereas the average American walks 1.5 miles).