Every Thanksgiving, there are a few things that can be counted on—the Dallas Cowboys and Detroit Lions will host an NFL game, your Aunt Nancy and Uncle Doug will get into a political argument across the table and somebody—if not everybody—will fall into a food coma after the big dinner.
The popular theory is the turkey is high in tryptophan, the mysterious chemical that lulls you into a deep slumber after a few bites.
But is tryptophan really the reason we’re so zonked out after turkey time? If you stop and think, many of us eat turkey all year round, and this tryptophan talk comes up only at the end of November. The answer: Tryptophan holds some responsibility for the inevitable Thanksgiving nap, but it’s really the carb-tryptophan combo that does you in.
Tryptophan is an amino acid that is necessary for the production of vital proteins and nutrients, and though it is always associated with turkey, there are actually higher per-gram quantities in everything from Cheddar cheese to sunflower seeds. It also produces serotonin, which enters the brain and is converted to melatonin, the hormone that regulates your sleep patterns and can cause drowsiness. However, in most cases, tryptophan reaches the brain in only minimal amounts, as other amino acids block its path.
This is where the carbohydrates come in. All those Thanksgiving side dishes—stuffing, mashed potatoes, gravy and cranberry sauce—are high in carbs, and when the body takes that in, it creates glucose. To break down that glucose, insulin is produced, and amino acids are taken from the bloodstream into the muscles. Tryptophan is not one of those amino acids, so with the rest of them out of the way, it has a free path to the brain. To add to that, your nervous system wants you to be still when digesting a hearty meal, so the nearest couch is a no-brainer. Next thing you know, you’re snoozing before the pumpkin pie is served.
And let’s be honest, after that Bloody Mary and a few glasses—or bottles—of red wine, nobody is going to believe your tryptophan cover story anyway.
So whether you’re hosting at your house or visiting the in-laws this year, when you’re face down in a pillow after a Thanksgiving feast for the ages, at least you can say, “Now I get it.”