Nov. 25, 2010 at 12:57 PM ETMake your post-Thanksgiving food coma work for you: New research suggests that eating a big turkey dinner may keep you from spending impulsively on holiday sales. The study, published in the December issue of the Journal of Marketing, builds on the turkey-tryptophan trope that we all hear this time of year -- it's practically guaranteed that somebody at your Thanksgiving gathering will say,"Did you guys know that turkey makes you sleepy?" That's only kind of true -- an amino acid called tryptophan is found in turkey, and it does work as a natural sedative, but we really don't eat enough of it, even at Thanksgiving, to be affected. Our after-dinner lethargy is more likely caused by overindulging on delicious carbs and cocktails. But the body uses tryptophan to produce serotonin, and serotonin is known to inhibit impulsive behavior, which made researchers from the University of Utah curious: How might Thanksgiving dinner affect Black Friday binge buying? To find out, they recruited 170 volunteers and instructed them to fill out an online survey on Thanksgiving evening in 2007. They rated how likely they were to buy popular items at a deep discount -- such as a Dell laptop marked down to $499. Those who had consumed a traditional Thanksgiving dinner were less likely to splurge on any of the marked-down items, say Arul Mishra and Himanshu Mishra, the University of Utah marketing professors that co-authored the study. (Fun fact: They're also husband and wife.) Of course, as Himanshu Mishra points out, "The influences are not going to be there after 12 hours. If someone is going out shopping tomorrow morning, probably the person will not see that effect." So here's how to make these new findings work for your wallet: Either skip the shopping on Friday and do your holiday shopping online Thursday night, or load up on leftovers before heading out to the stores on Friday. Would you give this a try? Or is impulse shopping on Black Friday half the fun? Find The Body Odd on Twitter and Facebook.