L-Tryptophan is an amino acid found in turkey that is a natural sedative. (Tryptophan helps the body produce the B-vitamin, niacin, which, in turn, helps the body produce serotonin. Serotonin calms the brain and plays a key role in sleep.) When people talk about how eating turkey makes you sleepy or the nap they’ll be ready to take directly after their Thanksgiving meal, they’re usually referring to the effect most people attribute to tryptophan.
I’ve recently become interested in the chemical reactions that occur inside your body when you eat different foods, thanks to Tim Ferris and his explanation of how the body metabolizes starches and sugars in The 4 Hour Body. As a result, I started wondering if there were ways we could control our sleepy reaction to eating turkey and avoid the seemingly-unavoidable post-meal Thanksgiving food coma. I figured maybe there are foods or other dietary supplements that will reverse or counteract the effects of tryptophan. What I quickly found when I began my research absolutely surprised me: Your Thanksgiving turkey will not make you sleepy. Let me repeat that in case you missed it:
Eat as much turkey as you want this Thanksgiving, because it’s not going to make you sleepy!
Really? Well, sort of.
It turns out that the effects of tryptophan are really not felt unless you ingest the stuff on an empty stomach, without much other amino acids or proteins in your digestive system. And it turns out that other foods, including chicken, seafood, and soy contain about as much tryptophan as turkey (see chart); and none of them get a bad rap for inducing lethargy. But the tiredness you feel after the Thanksgiving meal is certainly not a figment of your imagination. There are several other factors that contribute to that drowsy feeling such as:
Booze is a depressant and slows your system down. Drinking copious amounts of alcohol, which we often do on Thanksgiving, most certainly makes you lethargic.
2. Fat Consumption
Fats take a lot of energy to digest and slow down the digestive system. Consuming a lot of fat focuses the blood supply in your body on the digestion process and makes the rest of your body feel tired.
3. In-Law Anxiety
It takes a lot of energy to deal with stressful situations. Many folks find it quite stressful to spend time with their family and their spouse’s family on Thanksgiving. In fact, studies have shown that domestic disputes and domestic violence increase significantly on Thanksgiving. (Of course, I feel nothing but bliss when my in-laws come over!) Such stress can make you physically and emotionally exhausted by the time you sit down for your meal.
The more you eat, the more your body has to work to digest your food. And the process of digestion involves redirecting oxygen-rich blood from other parts of your body to your digestive tract. In turn, other parts of your body are getting less blood flow and you feel more tired.
Even though you may have guests that include a dozen screaming nieces and nephews, a drunk uncle with a loud mouth and a few siblings who still fight with each other like they did when they were 6-year-olds, the Thanksgiving meal can be euphoric and relaxing. That feeling (hopefully) persists long after the meal is over and the feeling of calmness is very similar to the feeling of tiredness.
All these factors together, therefore, and not so much the tryptophan, make you want to settle in for a long winter’s nap after that Thanksgiving meal.
– HowStuffWorks.com: Is There Something in Turkey That Makes You Sleepy?
– About.com: Does Turkey Make You Sleepy?
– World’s Healthiest Foods (whfoods.com): Tryptophan