Chocoholism really is an addiction. New research suggests that junk food may be as addictive as heroin. In research that will soon be published in the U.S., a neuroscientist found that a steady diet of sausages, fries, and cake programs the brain to crave more junk food. Dr. Paul Kenny found that rats on an unlimited junk diet needed increasingly more stimulation to register the same amount of pleasure as rats from the other groups. The research suggests that obesity and drug addition have common roots.