Parts of Experiment Spurlock's independent variable is the change in his eating habits to be exclusive to McDonald's items. As a second independent variable, Spurlock reduces the amount of walking he does from 4-5 miles a day to approximately 1.5 miles to be more typical of the average corporate worker. The dependent variable in Spurlock's experiment is his health. Because the experiment is designed to answer whether fast food can be healthy, his overall physical and mental health are what will be monitored and measured. Spurlock meets with three independent doctors to measure his health for the pretest. He also consults with a nutritionist and an exercise physiologist for more information. The results were recorded by each specialist before he applied the treatment. He returns to each doctor during the test and at the end of the thirty days to have his final measurements taken. This is the posttest. Researchers utilize control in order to increase the probability that findings accurately reflect the reality of the situation being studied. Typically studies are designed in such a way as to maximize the amount of control over the research situation and variables. To introduce control, Spurlock establishes 4 rules:
1. He can only Super Size when asked.
2. He can only eat food from McDonald's that is available over the counter.
3. He has to eat everything on the menu at least once during the 30 days.
4. He must eat three meals a day