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  • Writer's pictureFrank DiGiovanni

“Oh man, I ate too much turkey.”

Updated: Sep 8, 2022

That might be a familiar refrain heard during the next week. It is often followed by the person who said it slowly closing their eyes on the couch during a football game, movie or dog show. But is the tryptophan really the reason why Uncle Steve is snoozing through that exciting touchdown?

According to, tryptophan is an essential amino acid that serves several important purposes, like nitrogen balance in adults and growth in infants. It also creates niacin, which is essential in creating the neurotransmitter serotonin (a chemical that sends signals between your nerve cells). There are even two types of tryptophan: L-tryptophan and D-tryptophan. Now you might be thinking “What’s the difference, one letter?” Well you’re partially correct, and unless you’re a scientist, all you really need to know is, the only significant difference is the orientation of the molecule.

L-tryptophan molecule. Source: WikiMedia Commons

Don’t hate on the turkey for making you sleepy. Consider that tryptophan is found in a variety of foods, especially ones that are high in protein. For example, milk, eggs, cheese, fish, pumpkin and sesame seeds along with chocolate are known to be high in the chemical. Also, soy and tofu are high in tryptophan as well. So, you have the tryptophan coursing through you because of the turkey dinner you just gobbled down (sorry for the pun), but it needs to be converted in niacin (vitamin B-3). There must be enough vitamin B-2 (riboflavin), B-6 (pyridoxine) along with iron in your body to convert the tryptophan to the aforementioned niacin. With the proper amount of tryptophan in your body, you can expect more serotonin (the “feel-good” chemical), better sleep quality, depression and anxiety relief and better pain tolerance. There’s also the flipside to everything…Too much tryptophan can give you heartburn, stomach ache, nausea, headache and dry mouth.

So, what is it about Thanksgiving’s delicious spread of food that makes us sleepy? According to the USDA’s dietary guidelines, there is a range of how many calories a person should ingest: between 1,600 to 2,400 calories per day for an adult woman and 2,000 to 3,000 calories per day for an adult man. Keep in mind that these are only suggestions, and it is up to the individual to monitor their intake of food. Research from the New York Times and Calorie Control Council suggests that average Americans consume between 2,500 and 4,500 calories on Thanksgiving alone! For some, that means almost eating almost twice in one meal, what guidelines suggest you should eat through the course of an average day!

Thanksgiving spread. Courtesy Wikimedia Commons

Now I am not suggesting you starve yourself before you sit down to watch The National Dog Show or an NFL game, but consider taking a little less stuffing, mashed potatoes, turkey, etc. You probably don't want to consume an entire day’s worth, or more, of calories in one sitting! (You could be a marathoner who's carbo-loading, I'm not sure.) It is the high-tryptophan food and high carbohydrate intake that will almost guarantee that you find yourself dozing off on the couch. Scientific American’s blog has an interesting (and more in-depth) article by Janet D. Stemwedel, an Associate Professor of Philosophy at San José State University as to why Thanksgiving dinner makes you sleepy.

Didn’t listen or forgot and feeling like you ate too much? Consider a phrase my grandmother used to use after a big meal. Go take a “piccola passeggiata”, Italian for “little walk”. The increase in physical activity will help speed up your digestive system and decrease your sleepy feelings, among other things. You want another helping of knowledge? Head to for good further reading with “Is Walking After Eating Good for You?


Buon appetito!

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