If anyone's ever been food shopping on an empty stomach, then like me they would probably be guilty of buying lots of things that they didn't need, or at least something that looked appealing at the time.
Now research has found that this impulse is due to the secretion of a hormone that not only causes hunger but makes food look more appetising.
 
The Hunger Hormone
Researchers at the University of McGill in Montreal, Canada, have come up with another reason why we cave in to fast food when we're hungry, or why food advertising can be so effective at drawing us in.

When we are hungry, our brains release a hormone named ghrelin which indicates to our stomachs that we are hungry and it encourages eating. It has been found that this hormone has more of an effect on our brains and the amount we consume than previously realised.
 
Participants in the trial were administered ghrelin to monitor the effects that food would have on the pleasure sensors of the brain. They were given an all-you-can-eat buffet and it was found that those administered with ghrelin consistently ate more calories than those people given a placebo.
 
Food Appears Appetising
Next, the participants were shown a range of food and non-food images and their brains were monitored for additional activity. It was found that the ghrelin group could actually see the food images more clearly. Also, several regions of the brain were activate while viewing the food images, giving rise to a heightened sense of pleasure.

Researcher Alain Dagher of the Montreal Neurological Institute at McGill said, "Ghrelin has widespread effects. It's not one or two brain regions, but the whole network."

Controlling Hunger
It was noted that this research could have implications in the fight against obesity, however more work will need to be done to make sure that suppressing the hormone doesn't affect all the pleasure sensors in the brain. I might be wrong but a drug that turns you off food and makes you moody doesn't sound particularly appealing to me!