Insidermedicine In Depth – March 29, 2010 – Food Addiction

Brain changes that occur in individuals who overindulge on junk food until they become obese mimic brain changes seen in drug addiction, according to research published online ahead of print in Nature Neuroscience. Here are some facts about obesity: • In 2005, about 1.6 billion adults were overweight and at least 400 million were obese • By 2015, an estimated 2.3 billion adults will be overweight and more than 700 million will be obese • Already a major problem in high-income countries, rates of overweight and obesity are on the rise in low- and middle-income countries too Researchers from of The Scripps Research Institute in Jupiter placed electrodes into the brains of rats in order to directly measure the sensitivity of reward centers of their brains. They then divided the rats into three groups based on their access to tasty, calorie-rich foods of the type that are readily available to most people. The first group of rats had no access, the second group had access for only 1 hr a day, and the third had access for 18-23 hrs a day. During the 40 day study period, the rats with the extended access to the calorie-rich food grew to ingest nearly twice as many calories per day as the other rats and rapidly became obese. At the same time, the reward centers in their brains grew less and less responsive, requiring increasing amounts of stimulation to provoke a response. A similar pattern has been seen in rats exposed to heroin and cocaine. The specific brain cells that were …