I always figured they had crack in them. Doritos, too. And bacon.
The brains of rats had higher cellular activity in the "pleasure center" of their brains after consuming Oreo cookies. These are similar of being injected with cocaine or morphine. The study is done by Joseph Schroeder, an assistant professor of psychology and director of the Behavioral Neuroscience Center at Connecticut College.
To observe how "addictive" high-fat, high-sugar foods could be, researchers put the rats into a surroundings with two rooms. In one room, they were given Oreo cookies and in the other room, they were given rice crackers.
The experiment was repeated. The other groups of rats were given injections of cocaine or morphine in one room and saline in the other room. It was observed that in case of Oreo versus rice cake and cocaine versus saline, researchers found that "equivalent preference" was given by the rats for a room which contained Oreo cookies and the room in which they were given injections of morphine and cocaine.