Myth Buster: Thanksgiving Stupor—Is Turkey to Blame?

Myth: Turkey makes you drowsy.

Facts: On Thanksgiving, people do tend to become sleepy, but it’s because they eat a lot and on top of that commonly consume alcohol. It’s not turkey in particular—or even tryptophan, the often-blamed amino acid found in turkey—that causes fatigue, says Simon Young, a professor of psychiatry at McGill University in Montreal.

It is true that tryptophan in its purest form causes increased levels of serotonin in the brain, and one of the effects of serotonin is that it helps you fall asleep, Young says. Tryptophan is, however, just one of many amino acids that are the building blocks of proteins found in turkey, and the other amino acids balance any drowsiness from tryptophan, says Joan Salge Blake, the media spokesperson for the American Dietetic Association.

“The bottom line is, eat as much as you want on Thanksgiving, and if you need to, it’s OK to take a nap,” says Johanna Dwyer, director of the Frances Stern Nutrition Center at Tufts Medical Center in Boston.