 and 30 people as obese (BMI 30 or higher). Then they examined brain activity with functional magnetic resonance imaging (fMRI). Among lean participants, brain activity reduced across various regions of the brain following the infusion of both glucose and fat. Conversely, no changes in activity were seen in participants with obesity. 'This was surprising,' said Prof Serlie. 'We thought there would be different responses between lean people and people with obesity, but we didn't expect this lack of brain activity change in people with obesity.' Prof Serlie and her colleagues then took a closer look at a brain region called the striatum, which plays a key role in regulating eating behaviour through its 'reward' neurotransmitter, dopamine. Using fMRI to evaluate dopamine release following nutrient infusion, researchers found glucose induced a release in both groups of participants, while fat only caused dopamine release in lean participants, meaning there's reduced 'nutrient sensing' in obese people. Participants with obesity t){kind=link}
Dr Miriam Stoppard writes about a new study carried out by researchers at Yale University, US, that investigated why it is difficult for some people to lose weight and keep it off
Eating, feeling satisfied, stopping eating and not overeating, all involve quite a dance between the stomach and the brain. And it’s the messages from the stomach to the brain that makes us stop eating.
But this stomach/brain messaging service breaks down in people with obesity. It seems the brain doesn’t heed messages from the stomach.
This blunted brain response may explain why it’s difficult for some people to lose weight and keep it off, say researchers at Yale University, US.
“We need to find where that point is when the brain starts to lose its capacity to regulate food intake and what determines that switch” says Yale professor of medicine, Mireille Serlie.