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 we found out—and how you might be able to prevent drowsiness after a big meal.

Why Turkey Makes You Sleepy

There's a good chance the sleepiness is due in part to a compound called tryptophan. Tryptophan is an amino acid that your body cannot produce, so you need to get it from your diet, according to MedlinePlus.

"Turkey, which is typically the star of [a Thanksgiving] meal, is naturally high in tryptophan," Uma Naidoo, MD, a nutritional psychiatrist, professional chef, and the author of This is Your Brain on Food, told Health. Dr. Naidoo added that tryptophan "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 because the amino acid is actually quite helpful in other ways.

"Tryptophan is required for a wide variety of functions in the body," Georgia-based nutritionist Trista Best, RD, LD, told Health. "It is necessary for metabolic functions that impact mood, memory, visual cognition, and comprehension."

According to a small 2015 study published in the Archives of Psychiatric Nursing, increasing the intake of tryptophan from foods resulted in significantly less depression and irritability and decreased anxiety reported by study participants.

Does It Happen to Everyone?

Given tryptophan's widespread reputation for making you nod off, you may think that everyone is ready to pass out immediately after feasting on turkey. However, some folks will metabolize this amino acid in a different way 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," said Dr. Naidoo. "Knowing this, it is likely that some of us may be more or less sensitive to the sedative effects of tryptophan."

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

Does Any Type of Turkey (Like Turkey Lunch Meat) Do This?

As you know now, it's not uncommon to feel tired after eating Thanksgiving turkey. But what about the turkey sandwich from the deli around the corner? Can that cold-cut turkey be the cause of your post-lunch snooze at work?

In a nutshell, it's entirely possible that deli turkey is the culprit. "Tryptophan is an amino acid found in turkey, so it will similarly be found in turkey products like deli meat to some degree," explained Dr. Naidoo.

Tryptophan in Other Foods

Turkey is probably the first food that comes to mind when talking about tryptophan. But according to MedlinePlus, you'll find tryptophan in a lot of protein-based foods:

• Cheese
• Chicken
• Egg whites
• Fish
• Milk
• Sunflower seeds
• Peanuts
• Pumpkin seeds
• Sesame seeds
• Soy beans
  

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," explained Wong. So if these foods are also part of your Thanksgiving spread, they might be adding to your drowsiness.

How Much Does It Take To Feel the Effects?

Even though eating turkey seems to make you sleepy, it turns out that turkey doesn't actually contain a lot of tryptophan.

"A pharmaceutical dose of tryptophan to improve sleep is around 5 grams for adults, which is equal to 5,000 mg," explained 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 very 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," said 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 added that those cocktails you may have enjoyed throughout the day can also make you quite sleepy. The same is true for all those carbs and refined sugars typically eaten at the Thanksgiving meal, which Dr. Naidoo said can raise blood sugar levels for some people—thus rendering you ready for a nap.

Avoiding Post-Meal Drowsiness

A longstanding tradition, most Americans 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 a typical 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," said 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."

Instead of blaming the turkey for your post-meal drowsiness, try a few of these suggestions to enjoy the holiday and still have energy at the end of the day.