Why Does Turkey Make You Tired?

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.