Can't resist a piece of chocolate cake lying in front of you? Well, blame it on your hunger hormone, for a new study has revealed that ghrelin, a hormone in your gut, triggers you to eat more by making food look especially delicious and appealing.
Researchers from Montreal Neurological Institute, McGill University have revealed that ghrelin acts on specific regions of the brain to enhance our response to food related cues and eating for pleasure.
It was earlier thought that appetite was controlled by two separate mechanisms homeostatic which is regulated by hormones such as ghrelin, that act on the brain to tell the body when to eat in an attempt to keep a constant body weight.
And non-homeostatic or hedonic food consumption that is triggered by visual or smell cues.
The new study has shown that both consumption behaviours are inter-connected and ghrelin plays a key role in their regulation.
"Our study demonstrates that ghrelin actually activates certain regions of the brain to be more responsive to visual food cues, thereby enhancing the hedonic and incentive responses to food-related cues,' said Dr. Alain Dagher, neurologist at the Montreal Neurological Institute, McGill University and principal investigator in the study.
"Ghrelin is a hormone that triggers hunger, and is secreted by the stomach [when it is empty]. An easy analogy would be to think about when you go shopping on an empty stomach, you tend to buy more food and products higher in calories.
"The reason is that your brain views the food as more appealing, largely due to the action of ghrelin on the brain," he added.
For the study, participants were shown images of food and scenery [as a control] before and after receiving ghrelin intravenously during functional magnetic resonance imaging (fMRI).
In addition to analyzing the activation of different brain regions, subjects also answered questions about their mood and appetite before and after seeing sets of images. The effects of ghrelin on the amygdala and OFC correlated with the self-rated hunger ratings.
The study has shown that ghrelin action is more complex than previously thought and furthers the understanding of how drug treatment might be used to combat obesity.
The study is published in the May 7 issue of Cell Metabolism.