Every year, I I promise myself that I won’t eat myself into a food coma: I will eat responsibly, load my belly with salad, and eat little turkey and gravy. Instead, I wake up three hours after Thanksgiving dinner, sprawled like Robinson Crusoe on the living room floor under a pile of my nephews’ toys. My shirt is covered in light brown stains and greasy handprints stain my jeans.
What is it about Thanksgiving that sends me (and millions of other Americans) into digestive oblivion? Are we all in love with turkey or is there another reason why Thanksgiving is the holiday for laziness?
You’ve probably heard that turkey meat contains a sleep-inducing chemical called tryptophan. And while it’s true that those things contribute to the brain falling asleep, saying it does it on its own is like saying Neil Armstrong jumped to the moon alone.
For one thing, turkey isn’t particularly loaded with tryptophan. Ounce for ounce, a rotisserie chicken, grilled steak, or pork ribs have comparable amounts. Freeze-dried tofu has about twice as much tryptophan as turkey, and I doubt you’ll hear your Southern California cousin complaining about how sleepy he gets after gorging on fake meat.
Carbs are the real culprit of Thanksgiving sleepiness. Direct your heavy-lidded gaze toward the garnishes. Mashed potatoes, cranberry sauce, and pie are rich in carbohydrates and load your bloodstream with glucose, a sugar. To regulate the amount of glucose reaching the muscles, the body releases insulin, which requires a large amount of amino acids to help with the job. Tryptophan is also an amino acid, but it is not useful for regulating glucose. Instead, the body primarily uses it to produce hormones that regulate mood.
Normally, tryptophan has limited access to the brain as it is blocked by other amino acids. However, when called upon to help regulate glucose, tryptophan is clear. In the brain, it is converted to serotonin and then melatonin, which is known to cause drowsiness.
Türkiye is not special. Any food with a modest amount of tryptophan followed by about 30 grams of carbohydrates (a medium plate of spaghetti) will distract from the rest of the amino acids long enough to induce that feeling of brain fog. But the tryptophan/carbohydrate combination is only part of the reason for their lethargy. Most of the blame is on the fact that you eat. So. Curse. A lot.