Good health, family, friends—there’s plenty to be thankful for this Thanksgiving. Super savings can now be added to the list. People who enjoy a nice Thanksgiving meal are less likely to impulse buy, according to a study found in the Journal of Marketing Research.

The secret ingredient behind this information is tryptophan. Tryptophan is an amino acid that helps the body create and use serotonin. Serotonin is the body’s natural “feel good” drug. Serotonin helps regulate sleep and boost moods, but it’s also been known to have an effect on impulsive behavior.

For the study, researchers surveyed participants after Thanksgiving dinner. They asked participants to rank how likely they were to make certain purchases. Those who ate a traditional Thanksgiving meal were much less likely to impulse buy than individuals who ate pasta or burritos.

In a similar study, researchers examined how impulsive spending differed between vice products (such as ice cream) and virtue products (frozen yogurt). They categorized 170 college students as either impulsive or cautious spenders.

Regardless of how likely students were to impulse buy, the amount spent on virtue products was unaffected. Students who were prone to impulse buying spent more on vice products, while their counterparts were more likely to save money.

According to another report, roughly 62 percent of supermarket and 80 percent of luxury-good purchases by Americans are made on impulse. With stores dishing out some of their biggest bargains, the temptation to spend is likely to be high, and cutting impulsive spending could save some serious cash. The effects of tryptophan only last for about four hours, so you may want to grab a turkey sub before hitting the stores this Friday.

Read the source article by the Scientific American.