If you look at across the whole life cycle of growing corn, making ethanol and burning it in a car, and compare that to what happens when you find oil and make gasoline and burn it in a car, you only have about 15 percent less greenhouse gas going into the air from burning ethanol than you would if you're burning gasoline.
Although the food questionnaires used in the study did not ask about specific brands of cereals, popular brand-name cereals made from refined grains include varieties of Corn Flakes, Special K, and Rice Krispies, while examples of whole-grain cereals include Cheerios, shredded wheat, and bran.