Here in the U.S., it’s Thanksgiving week. And many of us are getting ready to stuff our faces, watch football and take advantage of all those Black Friday sales. But eat enough turkey and you may not want to shop. Because a new study, in the Journal of Marketing Research, shows that people who enjoy a traditional Thanksgiving meal are less likely to buy things on impulse.

We all know that turkey with all the trimmings can make you sleepy, in part because the bird is chock full of tryptophan. Tryptophan gets converted into serotonin, a brain chemical that affects mood and behavior. In previous studies, serotonin's been shown to inhibit impulsive behavior. So scientists got to wondering whether eating turkey would curb the urge to reach for a credit card. They asked subjects to fill out a questionnaire after dinner on Thanksgiving. And they found that people who’d eaten the traditional turkey were less willing to jump on a bargain than those who’d had lasagna or a burrito.

Mind you, the think-before-you-buy effects of serotonin wear off after a few hours. So to stop from shopping on Black Friday, you may need to top up with a late-night turkey club. And start the day with a turkey scramble.

—Karen Hopkin

[The above text is an exact transcript of the audio in the podcast.]