Why Does Turkey Make You Sleepy? Here's What to Know About Tryptophan

It happens to plenty of people: You eat your Thanksgiving meal, replete with a big pile of juicy turkey, and shortly thereafter you're lying on the couch ready for a nap. Why do we feel tired after our turkey-centered Thanksgiving dinner? You've probably heard that the main dish itself is to blame. But why exactly does turkey make you sleepy? Here's what experts say—and how you might be able to prevent the drowsiness after the big meal.

As you may know, there's a good chance it's due in part to a compound called tryptophan. "Turkey, which is typically the star of this meal, is naturally high in tryptophan," Uma Naidoo, MD, a nutritional psychiatrist, professional chef, and the author of This is Your Brain on Food, tells Health. "Tryptophan is an amino acid found in foods which helps support the healthy production of neurotransmitters including serotonin, which plays a role in producing the sleep-supporting hormone melatonin—which helps explain why eating turkey makes us sleepy."

While it might be a bummer that tryptophan can make you tired, don't get too annoyed at it, for the amino acid is actually really helpful in other ways. "Tryptophan is required for a wide variety of functions in the body," Georgia-based nutritionist Trista Best, RD, tells Health. "It is necessary for metabolic functions that impact mood, memory, visual cognition, and comprehension."

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Given tryptophan's widespread reputation of making you nod off, you may think that literally everyone is ready to pass out immediately after feasting on turkey. However, some folks will metabolize this compound in a different manner than others. "We all have highly unique microbiomes and biochemical profiles—especially when it comes to neurotransmitters and hormones—which influence how we digest and utilize the nutrients in food, as well as how they make us feel," says Dr. Naidoo. "Knowing this, it is likely that some of us may be more or less sensitive to the sedative effects of tryptophan."

That can also have an impact on how quickly the tryptophan takes effect, too. To that end, Dr. Naidoo suggests employing mindfulness while eating turkey so you can figure out your body's own tolerance of the compound—or lack thereof.

As you know by now, it's not uncommon to feel tired after eating a hot Thanksgiving turkey. But what about the turkey sandwich from the deli around the corner—can that cold cut turkey be the cause for your post-lunch snooze on regular work days? In a nutshell, it's entirely possible that it's a culprit. "Tryptophan is an amino acid found in turkey, so it will similarly be found in turkey products like deli meat to some degree," says Dr. Naidoo.

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Turkey is probably the first food that comes to mind when talking about tryptophan. But according to Best, you'll find tryptophan in a lot of protein-based foods. "Some of the highest tryptophan-containing foods include milk, tuna, poultry (turkey and chicken), nuts and seeds, oats, and even apples," she says.

Vancouver-based nutritionist Megan Wong, RD, gives the specifics on nuts. "Aside from turkey, nuts are also rich in tryptophan, especially pistachios, cashews, almonds, and walnuts," she says. So if these foods are also part of your Thanksgiving spread, they might be making you even drowsier.

Turns out, even though eating it always seems to make you sleepy, turkey doesn't actually have a ton of tryptophan in it. "A pharmaceutical dose of tryptophan to improve sleep is around 5 grams for adults, which is equal to 5,000 mg," says Best. "A serving of turkey is between 250 and 300 mg. Therefore, it takes quite a bit of turkey to cause drowsiness."

That means it's highly likely that tryptophan alone isn't solely responsible for your sleepiness. "Turkey isn't especially high in tryptophan—there's actually a bit more in chicken—so that post-Thanksgiving meal drowsiness is more likely due to overeating," says Wong. "That and the fact that you're overeating high-fat dishes. Research has shown that after a high-fat meal, an increased level of the hormone cholecystokinin (CCK) leads to drowsiness."

Dr. Naidoo adds that all of those cocktails you've been enjoying throughout the day can also make you quite sleepy. The same is true for all those carbs and refined sugars typically consumed on Thanksgiving, which Dr. Naidoo says can do a number on your blood sugar levels—thus rendering you ready for a nap.

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As is longstanding tradition, the vast majority of Americans will sit down for a large meal featuring turkey as the main course on Thanksgiving. And chances are you'll be tempted to eat more than you would on any normal day. But if you need to be awake and alert, it's best to enjoy food and alcohol in moderation. "To avoid post meal drowsiness it is important to not eat past your body's fullness," says Best. "Don't stuff yourself at the meal to the point of being uncomfortable. It is also important to make sure you are hydrated as this will help with energy as well."

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