This is Scientific Americans 60 Second Science.

I'm Karen Hopkins.

Tis the season for overeating.

But it's not just your lack of willpower or the omnipresent holiday treats.

No, you can lay some of the blame on Gerellen.

Because a new study shows that Gerellen, the hormone that makes you hungry,

also makes food

smells, irresistibly appealing.

The finding appears in the journal,

Cell reports.

Grellin is produced in the stomach, and its levels rise

before your habitual meal times and after you haven't eaten for an extended period.

So the hormone reminds you to put something in your belly.

Injecting rats with Gerellen encourages them to eat.

And people who receive a dose of Gerellen grab extra

helpings from the buffet. But how does the hormone induce all for indulgence?

To find out, researchers at McGill University trained volunteers to associate random images with the

smell of food.

For example, every time they saw a tree, they might get a whiff of freshly baked bread.

At the same time, some of the subjects received Grellin, others got only saline.

The volunteers were then ushered into an FMRI machine, where the researchers watched their

brains to see which parts got turned on by different images.

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