Friday, October 17, 2008

Obese People's Brains Show Less Pleasure From Eating

“New research from the US suggests that certain people may have a genetic predisposition to obesity because the reward centres in their brains respond sluggishly after eating, so to get more pleasure from eating they opt for foods denser in calories, which makes them gain weight. The study was done by Eric Stice, psychology researcher at The University of Texas at Austin, and colleagues from other establishments in the US, and is published in the 17 October issue of Science. Stice has been studying eating disorders and obesity for nearly 20 years. He said that this study: ‘Reveals obese people may have fewer dopamine receptors, so they overeat to compensate for this reward deficit.’ When a person eats, their brain's reward centre responds by releasing the messenger molecule dopamine. But Stice and colleagues found that compared to the brains of lean people, the brains of obese people showed less activation in the striatum, the part of the brain that expresses dopamine receptors. The researchers also found that individuals whose striata were less active during eating were the ones most likely to become overweight, particularly if they had a gene called TaqIA that is linked to having fewer dopamine receptors. Stice said that people with fewer dopamine receptors: ‘Need to take in more of a rewarding substance -- such as food or drugs -- to experience the same level of pleasure as other people.’”

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