People may also choose junk food simply because they have developed a mild physical dependence on it. Studies show that binge eating foods high in sugar or fat results in neurochemical changes in the brain similar to those that develop in drug addiction. According to a study published in “Physiology and Behavior” in October 2011, rats that habitually eat foods high in sugar and fat mentally crave more of those substances and experience withdrawal-like symptoms if they do not get access to it. After developing the habit, people may be neurochemically driven to choose junk food.