I know what you’re thinking… “Oooh! Pick me, pick me! I know this one! It’s ’cause turkey contains tryptophan!”
Sorry there, champ. It’s not the tryptophan in turkey. While tryptophan is an amino acid that is linked to sleepiness, there are plenty of food items that contain just as much if not more tryptophan than turkey, and none of them have a reputation for making you tired. In fact, chicken, beef, and pork all have the same amount of tryptophan as turkey. Egg whites have as much as four times the amount. Have you ever heard people talking about how they need to take a huge nap every time they eat an egg white omelette for breakfast, a hamburger for lunch, or a nice pork chop for dinner? Me neither.
In fact, the real answer has nothing to do with turkey, but it does have something to do with tryptophan. While turkey doesn’t make us especially drowsy, we tend to consume turkey as part of a large feast involving lots of complex carbohydrates (mashed potatoes, stuffing, rolls) and big portion sizes. Studies have shown that carb-rich meals start a chain of biological effects that eventually results in higher levels of tryptophan uptake, leading to increased production of serotonin and eventually melatonin, a hormone that regulates sleep in humans. So, most likely, it’s not the turkey that’s making you drowsy… it’s all the other stuff you eat at Thanksgiving that pushes you over the edge.
If you’re sad to learn that one of your favorite holiday myths is just that (a myth), take heart! There’s plenty of things to be happy about. Like the fact that the Wikipedia article on tryptophan says that it is “an essential amino acid in the human diet, as demonstrated by its growth effects on rats.” (Non sequitur anyone?) Or like this YouTube video of a guy gobbling at turkeys…