Trick question. It doesn't. The myth that tryptophan, an amino acid found in turkey, makes you sleepy, is just that. A myth.
In reality, tryptophan is found in many protein-rich foods, including nuts, seeds, soy, cheese, eggs, fish and chicken, according to Kim Larson, a registered dietitian nutritionist and spokesperson for the Academy of Nutrition and Dietetics and owner of Seattle-based Total Health.
"Turkey is not the only food we get tryptophan from, and it’s in relatively average amounts in turkey," Larson said. "It's not the highest source."
But anecdotally, you've felt the urge to post up on the couch after Thanksgiving dinner, right? That sleepy feeling isn't all in your head. It's actually caused by the combination of tryptophan with high quantities of carbohydrates.
"Carbohydrates are the vehicle that really drive the sleepiness, especially excessive amounts of them," Larson said.
Tryptophan competes with other amino acids to enter the brain, and carbohydrates trigger the release of amino acids-suppressing insulin. One of the amino acids insulin doesn't block, however, is tryptophan, giving it free reign to enter the brain without competition. Once all of that free-wheeling tryptophan hits the brain, it's metabolized into melatonin, your body's natural sleep aid.
Other sleep-inducing culprits on your Thanksgiving tabletop include refined sugars -- hello, pecan pie -- and, you guessed it, alcohol.
Limiting how much you drink and alternating your alcoholic beverages with water or non-alcoholic drinks, which slow alcohol's absorption into the body, can help keep you alert long past when the last dessert plate's been cleared, according to Larson.
Even better, work family-friendly physical activities like hiking and backyard football or indoor games like Ping-Pong into your celebration to boost energy, encourage digestion and avoid mindless snacking before the main event.
The bottom line is that Thanksgiving comes just once a year. If you're going to indulge and sleep, indulge and sleep. Just don't blame the turkey.
"Ask Healthy Living" is for informational purposes only and is not a substitute for medical advice. Please consult a qualified health care professional for personalized medical advice.
Also on HuffPost:
Turkey Mistakes Not To Make
Problem: It's hard to know when the turkey is done.(01 of11)
Open Image ModalSolution: It's time to get yourself a trusty instant-read thermometer and take the turkey's temperature. Just insert a meat thermometer into the area where the thigh and breast meet -- it should register 160 degrees F when it's removed from the oven, and 165 degrees F after it has rested. If you've stuffed the bird, take the temperature of the stuffing (160 to 165 degrees F also). You can also make an incision where the thigh and breast meet -- if the juices run clear, not red, then the bird is done. Whatever you do, don't rely on those plastic pop-up timers that are stuck in the bird -- all they do is let you know your bird is dry and overcooked (most of them don't pop up until the temperature reaches 180 degrees F!). One great gadget for perfect turkey-cooking is a probe-style thermometer, which you can leave in the bird, leading out a wire to a display that will signal once the bird is done. (credit:Alamy)
Problem: The turkey is dry and flavorless.(02 of11)
Open Image ModalProblem: The turkey looks pale and flabby.(03 of11)
Open Image ModalSolution: A beautifully browned bird is impressive and tastes pretty amazing. If you're having trouble getting a golden brown skin, there are a few things you can do. Before you put the bird in the oven, rub the skin with soft butter or olive oil -- lots of it. This will help the skin brown better and it will make it taste good. Also, don't forget to baste the bird. Another unique method that helps produce a brown skin is the cheesecloth method. Basically dip the cheesecloth in your basting liquid and drape it over the bird. During roasting, baste the bird as usual -- the cheesecloth will turn almost black. Remove it once the turkey is done and you will be left with the most glorious crackling skin in a shade of mahogany. (credit:Aimee Herring)
Problem: The turkey is burning.(04 of11)
Open Image ModalSolution: Aluminum foil is your friend. If you notice that the turkey is browning too quickly, tent it with aluminum foil to redirect the heat away from the skin. You might have to pick off some extra-black skin, but at least you've prevented a disaster.
Some cooks like to prevent this altogether by roasting the bird tented with aluminum foil during the first half of cooking time. Another method is to roast the bird upside down (with the breast down) for the first half of cooking time and then flip it over onto its back to finish roasting, but don't make yourself crazy attempting that with a giant bird. (credit:Alamy)
Problem: The turkey is still frozen.(05 of11)
Open Image ModalProblem: There aren't enough pan drippings to make gravy.(06 of11)
Open Image ModalProblem: The turkey is cooked unevenly.(07 of11)
Open Image ModalSolution: An unevenly cooked turkey is almost always a result of not trussing properly -- or an oven that doesn't cook evenly.
Large poultry should always be trussed (i.e. tied up). All the technique requires is tying up the turkey with kitchen twine. This ensures even cooking because it pulls the wings and legs toward the body of the bird, preventing them from splaying outward. This allows the hot air in the oven to circulate easier
If you believe your oven doesn't heat evenly, try rotating the roasting pan a couple of times during cooking. And use an oven thermometer to tell what the temperature is. The oven should be set to between 325 and 375 degrees F. (credit:Richard Theis / EyeEm via Getty Images)
Problem: The turkey is undercooked.(08 of11)
Open Image ModalProblem: The turkey falls apart when I carving it.(09 of11)
Open Image ModalProblem: Not sure what to do with the innards.(10 of11)
Open Image ModalSolution: Whatever you do, don't forget to remove the gizzards, heart, liver, kidneys and neck from the turkey cavity. You don't want to roast the turkey with the innards inside (especially if they're in plastic bags!).
Instead, use them to make stock, which in turn can be used for moistening stuffing or for gravy. Some people choose to roast or saute the giblets and neck beforehand and then make a stock from the roasted meat. This will give you a much deeper flavor. Make sure not to roast the liver or include it in your stock -- liver will turn your stock cloudy. Chop the liver and add it to the stuffing, for extra heartiness. (credit:Alamy)
Problem: To stuff or not to stuff?(11 of11)
Open Image ModalSolution: Stuffed turkey is traditional, but that doesn't mean you have to stuff your bird. Many people actually prefer stuffing or dressing baked separately from the bird. It can actually develop a nice crust instead of remaining soggy which happens when it's cooked inside the bird.
If you've chosen not to stuff, know that the bird will roast faster, but don't leave the cavity empty. Add some herbs, maybe half a lemon, and/or an apple -- these aromatic ingredients lend the bird lovely flavor. If you've chosen to stuff the bird, make sure you do it just before the turkey goes into the oven, otherwise, if done too early, the stuffing will absorb bacteria from the cavity. Make sure to pack the stuffing loosely -- do not compact the mixture or it won't cook properly. Take the temperature of the stuffing, not just the bird. The temperature should register between 160 and 165 degrees F. (credit:Alamy)