Obesity causes food ‘addiction’
Gaining weight may desensitize the brain to the pleasure we get from sugary and fatty foods, prompting us to eat more cookies and cake than we did when we were leaner, research shows. A similar effect is seen in drug users, who eventually require more cocaine or heroin in order to achieve their original high.
In a study published Sept. 29 in the Journal of Neuroscience, researchers scanned the brains of women as they drank a milkshake. They saw the sugary drink activated an area known as the striatum. Half a year later, the researchers repeated the experiment on the same women — some of whom had gained some weight. The more weight the women had put on in the interim, the less their brains responded to the milkshake in the second experiment.
Research on animals has also shown rats fed a diet rich in sugar and fats are less sensitive to the pleasure-inducing neurotransmitter dopamine.