<p>Researchers at the University of Texas study found that the reward pathways in the brains of overweight people become less responsive as they gain weight.This causes them to eat more to get the same pleasure from their food, which in turn reduces the reward response still further, they said.<br /><br />Lead researcher Eric Stice, a psychologist at the university, said the result suggested that overeating may push people onto a slippery slope akin to a drug addict's craving for ever-larger doses.<br /><br />"People are having to eat more and more to chase the high," Stice was quoted as saying by the New Scientist.For their study, Stice and colleagues used fMRI brain scans to monitor 26 obese or overweight volunteers as they sipped either a tasty milkshake or a flavourless liquid resembling saliva.<br /><br />They compared the effect of both drinks on brain activity in the dorsal striatum, a key part of the brain's reward circuitry -- the neurological corridors that respond to pleasure — after eating.<br /><br />Six months later, they retested the volunteers. Those who had gained weight since the first test also showed reduced activity in the dorsal striatum in response to the milkshake.In contrast, no change was seen in people who had lost or maintained weight, they reported in the Journal of Neuroscience.<br /><br />Obese people are known to have fewer pleasure receptors in the brain than thin people to start, according to the researchers, whose findings suggest that overeating blunts the reward pathway further.<br /><br />However, the researchers said it remained to be seen whether losing weight can reverse the cycle and restore normal functioning of the reward pathway.<br /></p>
<p>Researchers at the University of Texas study found that the reward pathways in the brains of overweight people become less responsive as they gain weight.This causes them to eat more to get the same pleasure from their food, which in turn reduces the reward response still further, they said.<br /><br />Lead researcher Eric Stice, a psychologist at the university, said the result suggested that overeating may push people onto a slippery slope akin to a drug addict's craving for ever-larger doses.<br /><br />"People are having to eat more and more to chase the high," Stice was quoted as saying by the New Scientist.For their study, Stice and colleagues used fMRI brain scans to monitor 26 obese or overweight volunteers as they sipped either a tasty milkshake or a flavourless liquid resembling saliva.<br /><br />They compared the effect of both drinks on brain activity in the dorsal striatum, a key part of the brain's reward circuitry -- the neurological corridors that respond to pleasure — after eating.<br /><br />Six months later, they retested the volunteers. Those who had gained weight since the first test also showed reduced activity in the dorsal striatum in response to the milkshake.In contrast, no change was seen in people who had lost or maintained weight, they reported in the Journal of Neuroscience.<br /><br />Obese people are known to have fewer pleasure receptors in the brain than thin people to start, according to the researchers, whose findings suggest that overeating blunts the reward pathway further.<br /><br />However, the researchers said it remained to be seen whether losing weight can reverse the cycle and restore normal functioning of the reward pathway.<br /></p>