Newswise — Recent studies show that 65 percent of the U.S. population is either clinically obese or overweight. Over-consumption, or binge eating, of high amounts of fats, carbohydrates and sugar is, according to some researchers, largely responsible for this epidemic. A University of Missouri-Columbia researcher has discovered an area of the brain that appears to control the intake of high-fat foods.

"Interestingly, this region only controlled feeding that occurred after the subject reached fullness, and had no effect on the normal response that hunger brings," said Matthew Will, an MU assistant psychology professor, who conducted the study along with Ann Kelley of the University of Wisconsin-Madison.

Prior research, Will said, has determined that the release of opioids, which are "pleasure" chemicals in the brain that can cause euphoria, into a region of the brain called the nucleus accumbens, controls the intake of highly palatable, or tasty, foods like ice cream. This chemical release increases the intake of fat and sugar-containing foods by 300 percent. Using this method as a model for binge eating, Will and Kelley found that while deactivating the basolateral amygdala, a section of the brain located in the temporal lobe that affects emotion and motivation, had no effect on the normal consumption of a high fat diet, it completely prevented the binge eating of fat produced by the opioid activation of the nucleus accumbens.

In the study, Will examined different groups of rats where the release of opioids in the nucleus accumbens occurred with either the simultaneous inactivation of the amygdala or a controlled saline solution. The rats were then put in cages with a jar containing high-fat food. Will found that the rats that were administered opioids into the nucleus accumbens ate three times more fat than the rats given the saline solution. However, those rats in which the basolateral amygdala was inactivated did not binge.

"Given the current epidemic of obesity, understanding how these networks in the brain control the desire for food is extremely important," Will said. "This research demonstrates that a specific brain region may be responsible for feeding beyond the basic metabolic needs signaled by hunger, such as those instances when you can't turn down that delicious chocolate chip cookie, or when you simply need an emotional boost from a bowl of ice cream."

Will's study was published in the August edition of NeuroReport.

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CITATIONS

NeuroReport (Aug-2004)