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If you’ve ever curled up on the couch after a Thanksgiving feast to catch a few winks, you may have also wondered about that old holiday rumor about turkey: The bird contains tryptophan, which appears to be some kind of natural sleep aid.

But is there anything to the turkey-tryptophan-tired idea, or is it a Thanksgiving-themed myth to justify avoiding the post-meal cleanup?

The short answer is no, a few slices of turkey aren’t enough to knock you out. The science of sleepiness after a Thanksgiving meal is a little more complicated.

In addition to the effect that consuming a lot of carbs and calories in a short time has on your body, the time of year plays a role in your holiday sleep cycle, too.

But fighting off the zzz’s this Thanksgiving or any day that features plenty of food and drink can be done pretty simply — it just takes a little planning and little self-control.

First things first: Yes, turkey does contain tryptophan, which does promote good sleep and a good mood, according to research published in Neuroscience and Biobehavioral Reviews.

Tryptophan is one of several essential amino acids, which are considered the building blocks of proteins in animals and plants.

Specifically, tryptophan is involved in the production of serotonin (a hormone that helps regulate mood) and melatonin (a hormone that helps regulate your sleep cycle), according to a 2016 review of studies on how tryptophan affects the body.

Adults who take tryptophan supplements take doses of 5 grams before bed to help improve sleep. By comparison, two servings of turkey contain about 410 milligrams of tryptophan — close to the daily requirement of this important nutrient.

But that also means you’d have to eat 20 servings of turkey to equal one dose of tryptophan in pill form. That’s a lot of trips to the buffet!

Other sources of tryptophan

Interestingly, turkey isn’t the only big source of tryptophan in the average diet. Other good sources include:

  • milk
  • cheese
  • beef
  • chicken
  • nuts
  • soybeans

What’s interesting about this is that these foods never earned the same sleepy rap that turkey has. You’d never hear anyone complain, for example, “Oh, that grilled cheese sandwich just put me right out.”

The truth is, tryptophan-rich turkey is just one of many contributors to celebration snoozes. Think about all the other holiday staples, like mashed potatoes, stuffing, pie… the mouthwatering list goes on!

Consuming such high carb foods can cause a quick rise in your blood sugar, which in turn can bring on a crash that features fatigue and reduced alertness within the first hour after ingestion, according to a 2019 study.

Couple your body’s response to all that food with alcohol’s sedating effects, and you have the making of at least a short winter’s nap after dinner.

Circulation issues

A big meal of any kind can also cause a change in circulation that affects your energy and focus. When more blood is needed in the stomach to digest turkey, gravy, and the rest of dinner, less blood is available in the brain to keep you awake.

This may be why you don’t feel sharp enough to answer trivia questions or make halfway reasonable guesses about your partner’s charades clues.

Time of year

It’s also worth noting that late fall and early winter are also accompanied by earlier arrivals of darkness in the late afternoon across much of the northern hemisphere.

Melatonin, the sleep hormone, is geared to start making you sleepy when the day turns dark. So as much as you may want to stay up for more football on Thanksgiving, your body’s circadian rhythms are telling you it’s time to get some shut-eye instead.

To keep wide awake during Thanksgiving or any holiday celebration, consider the following tips:

  • Eat more slowly. Give your body time to realize how full it is and that it doesn’t need another serving of your aunt’s three-bean casserole. The body needs about 20 minutes to realize it’s full, so take your time — you’ll eat less.
  • Take smaller portions. This may seem like heresy, but being able to see your plate is a good thing. Taking less food to start your meal often means you’ll eat less by the end of it.
  • Eat healthy snacks or small meals before your holiday dinner. Starving yourself in anticipation of a delicious feast can lead to overindulgence.
  • Watch the alcohol intake. Current guidelines recommend that women have no more than one drink per day and that men have no more than two drinks. But alcohol is also a temporary sedative, and its effects can be enhanced with overeating.
  • Stop eating when you’re full. This may lead to more leftovers to enjoy the next day.
  • Take a walk after dinner. This will put some of those carbohydrates to work by giving you energy — and it’ll make you feel better than lounging on the couch half asleep.
  • Get 7 to 8 hours of sleep on a regular basis. Keeping odd hours can make you more likely to conk out at inopportune times.
  • Exercise regularly. This will help you maintain a healthy energy level.

While tryptophan can certainly play a small role in feeling sleepy after turkey time, it’s really the combined effect of several different things.

A big high carb meal, alcohol, a change of seasons, and possibly other lifestyle behaviors can really help make those eyelids heavy after dinner.

If a post-meal nap is part of your holiday tradition, there’s nothing really wrong with it. But if you want to stay alert, focus on eating and drinking a little less this year — and on maintaining healthy habits during the other days of the year.