There might be more than a few myths surrounding Thanksgiving. For instance, was the first Thanksgiving really a harmonious gathering between pilgrims and native Americans that took place under the shadow of November foliage? The answer is foggy. But the mythos doesn't die with our bungled conception of history, because there's one Thanksgiving controversy that's managed to roil and fester to this day, and it starts at your dinner table: tryptophan.
As legend has it, turkey contains an excess amount of tryptophan, an amino acid that makes you sleepy. So, when you see a slow tide of lethargy washing over everyone at your Thanksgiving party, the nasty T-word might come to the fore. But it turns out your uncle's food-borne coma isn't brought on by some nefarious chemical harbored by America's turkey population.
It's true that tryptophan is the precursor to serotonin, which has a strong effect on many bodily functions, chief among which is healthy sleep. But turkey doesn't contain any more tryptophan than other widely consumed meats, including other poultry. In fact, as Live Science explained in a 2013 article, cheddar cheese is more tryptophan-riddled than turkey. While tryptophan produces serotonin, which is eventually converted into melatonin en route to making you tired, the presence of a variety of amino acids in turkey often negates the effects of tryptophan.
The real punishment of Thanksgiving, the one that makes you feel like a lifeless tub of goo in a Sisyphean battle against calories, is actually brought on by carbohydrates. As a report by Wired explains: "Any food with a modest amount of tryptophan followed by about 30 grams of carbs (a medium plate of spaghetti) will distract the rest of your amino acids long enough to induce that foggy-brain feeling."
What happens, basically, is that carbs trigger the release of insulin, which removes all the other amino acids from your bloodstream. When all of this goes down, tryptophan remains the sole amino acid in your blood. From there, it eventually moves into your brain, where it slowly morphs into the drowsiness-causing melatonin. This doesn't account for all the drinking you're probably doing before, during, and after you start masticating like a possessed, food-vacuum.
But the ultimate takeaway for Thanksgiving zombies out there: eating massive amounts of anything -- especially when coupled with alcohol -- is going to make you tired. Thanksgiving is a bonafide feeding frenzy, but there isn't some mysterious chemical that's solely to blame for your afternoon spent watching football with a beer resting on your gut.
It's you, the gluttonous, turkey-gobbling American.