Why Does Thanksgiving Dinner Make You Sleepy?

It’s Thanksgiving in the U.S. The dining room table is overflowing with all the trimmings — mashed potatoes, sweet potato casserole, stuffing (or dressing), cranberry sauce, dinner rolls and of course, the star of the show, the glistening, golden turkey.

You tuck into a full plate, excited and overwhelmed by all the wonderful food at your fingertips. Thank goodness you wore your stretchy pants — you’re going to need them.

Whether you clean your plate or leave a few forkfuls of Brussels sprouts behind, it doesn’t take long before you start to crash. You’re sleepy, sluggish, lethargic and feel like you can’t eat another bite (but wait, there’s three kinds of pumpkin pie, a pecan pie and Grandma’s cookies). Yikes.

Many of us attribute this sloth-like feeling to turkey (and more specifically, to tryptophan). But is that really true? Could other habits and behaviors also account for why we pass out on the couch after a big meal?

Registered dietitian Julia Zumpano, RD, LD, explains why turkey is just part of the recipe to feeling sleepy on Thanksgiving.

Does turkey make you sleepy?

Tryptophan is known to cause drowsiness — and it can be found in turkey.

A serving size of turkey, which is about 3 ounces, contains anywhere between 250 milligrams to 300 milligrams of tryptophan.

So, what is tryptophan exactly? It’s an essential amino acid that’s used to make proteins. And you can only get tryptophan from the foods you eat.

Turkey isn’t the only food with tryptophan. Other foods that contain it include:

• Milk.
• Eggs whites.
• Chicken.
• Fish.
• Canned tuna.
• Oats.
• Cheese.
• Sunflower seeds.
• Peanuts.
• Pumpkin seeds.
• Sesame seeds.
• Soybeans.

A key point of clarification, though? You’d have to eat a lot of these foods — including turkey — to feel drowsy.

So, why do you feel sleepy after Thanksgiving dinner or another big meal? You need to look at the whole picture.

“You might feel mildly tired after eating turkey,” says Zumpano. “But the tryptophan is not the only reason.”

Other reasons why you may feel sleepy after eating Thanksgiving dinner

Eating turkey is just one piece of the drowsiness puzzle when you eat a big meal like a turkey dinner. Here are some other reasons why you may feel sleepy after Thanksgiving dinner:

You eat too much

You probably tend to overeat during Thanksgiving dinner. And consider the types of foods you’re eating, says Zumpano.

“The meal typically contains large amounts of carbs (stuffing, potatoes, pie, desserts, rolls), which can spike your blood sugar initially,” she continues. “But then, your blood sugar levels crash or decrease, which leaves you feeling lethargic.”

Your body increases blood flow to your stomach

To handle the large amount of food in your stomach, there’s a change in your blood circulation.

“Your bowels need more blood to digest the large meal, which may lead to less blood to your brain causing you to feel less alert,” explains Zumpano.

You may have had a few alcoholic drinks

You don’t just have to contend with all the delicious food options. You may also feel like having a cocktail, glass of wine or beer with your meal.

“When you’re adding alcohol in the mix, that’s going to make you feel that more lethargic, more relaxed feeling on top of a big heavy meal,” Zumpano adds.

How to avoid drowsiness after eating a big meal

What can you do to combat that post-meal crash? Zumpano shares a few tips:

• Eat smaller portions. It’s OK to indulge in all your Turkey Day favorites, but eating a smaller amount of food can help you avoid feeling tired afterward.
• Limit alcohol. You’re in a celebratory mood — and that may mean you want to have an alcoholic drink (or two or three) with your friends and family. Zumpano says it’s a good idea to limit how much you drink and to make sure you’re drinking water throughout the meal (and day), too.
• Slow down. With all those yummy choices, you may tend to eat quickly. But Zumpano advises to slow down and enjoy the food you’re eating. Try eating with your nondominant hand, which can really help you slow down.
• Stop eating once full. Are your eyes bigger than your stomach? If so, that’s OK. You may feel like you need to eat every last morsel on your plate. But Zumpano says that you shouldn’t force it. In fact, pay attention to how long you’ve been eating and when you reach the 10- to 15-minute mark, take a moment to assess how you’re feeling. If you feel full, then stop eating. Try using a smaller plate or filling your plate with vegetables first, as those don’t tend to be as filling — that will leave less room for the meat and carbs.
• Talk a walk. It’s probably the last thing you feel like doing, but going for a walk around the neighborhood (or any form of exercise like a Turkey Trot race) can help your digestive system work through that heavy meal you just ate. Plus, activity will keep you alert and increase your energy.
• Get a good night’s sleep the night before. The holidays, while fun, can be stressful. You have to make dinner, clean the house, entertain out-of-town guests and deal with any family drama. Zumpano says all those factors can lead to a lack of sleep. “It’s important to get enough rest, because that’s also going to increase the effects of the meal if you’re already tired to begin with,” she explains. “And it may also lead to you making poor decisions when it comes to eating.”

Give thanks!

It can be tempting to load up your plate with all Thanksgiving dinner has to offer. But if you don’t like how you feel afterward, remember that you’re in control.

“If it’s a part of Thanksgiving that you don’t particularly enjoy, know that you can change the outcome,” encourages Zumpano. “You can take steps like watching how much you eat and drink exercising and getting enough sleep beforehand.”