Why Does Turkey Make You Sleepy?

It's a well-established Thanksgiving tradition for most families: We cook for days, eat a giant meal, and then, before we know it, we're napping on the couch.

It seems nearly certain that there's something uniquely exhausting about Thanksgiving dinner. But what is it? Is it all the prep that goes into it? A heavy meal? Or, maybe just the exhaustion of all that extended family time?

Common wisdom (and grandmothers) tell us it's the turkey's fault. But why would poultry make us drowsy? We asked experts to explain why, yes, turkey could make you sleepy — but also why it's not the only factor making us crave zzz's.

Does Turkey Really Cause Sleepiness?

"Turkey is associated with sleepiness because it is a good source of the amino acid tryptophan," says Holly Klamer, MS, RDN, a Michigan-based registered dietitian nutritionist. "Tryptophan is then used by the body to help make the neurotransmitter serotonin. Serotonin is considered a precursor to the hormone melatonin."

Melatonin is a main regulator for sleep. That's why you see it in many sleep supplements.

But it seems that we only hear about tryptophan when we're discussing turkey dinners, and there are actually a lot of other ways to get it. Why then is turkey always to blame?

"In addition to tryptophan, turkey and other meats provide many other amino acids. Therefore, it is not just a rush of tryptophan to the brain after eating turkey but rather a combination of amino acids," Klamer says.

Plus, tryptophan can be found in other foods as well, such as chicken, beef, and even pork chops. And it's not just meat — tofu and some fish are also high in tryptophan, and no one ever accuses them of making them sleepy.

This is where the plot does indeed thicken (much like a great gravy!). Interestingly, carbohydrate-rich foods can also play a role in making you feel sleepy.

"Carbohydrate-rich foods like mashed potatoes and desserts can signal the brain to increase levels of serotonin regardless of how much tryptophan is eaten," Klamer says. Most Thanksgiving tables are filled with carb-heavy recipes, so it seems everyone is really giving turkey a hard time. It is not just the poultry alone that causes the post-turkey torpor.

"Other factors contributing to our feeling sluggish and downright sleepy after a Thanksgiving meal are that we have just spent several hours eating a large-sized meal, often with alcohol and heavy desserts, which can take a toll on our digestion," says Dr. Lauren Broch, who holds a master of science degree in human nutrition, and a doctorate in psychology with specialized training in sleep disorders.

Turkey Day comes at the end of a long year and marks the start of a busy season, so maybe we can embrace that cozy sleepy feeling while it's there. A post-meal nap never hurt anyone.

But if you are trying to avoid that sleepy feeling and make the most of the holiday, practice some moderation, and move around a bit more before and after the meal.

"To decrease your risk of getting sleepy, drink plenty of water before you eat, eat more vegetable side dishes, use a dessert or smaller plate, and eat smaller portions. Skip having seconds and instead go for a walk after dinner," says Dr. Monique May, Medical Director at Aeroflow Sleep.