Feeling tired after eating happens to the best of us here and there, especially after a big meal. Like, who among us hasn’t had the urge to take a nap after chowing down on Thanksgiving? But if you find that you regularly feel wiped after you eat, it’s understandable to have questions.

For the record, yes, this is a thing. It’s known as postprandial somnolence, which is basically a fancy word for a food coma, says W. Christopher Winter, MD, a neurologist and sleep medicine physician with Charlottesville Neurology and Sleep Medicine and host of the Sleep Unplugged podcast. “Feeling tired after eating a big meal is pretty normal,” Dr. Winter says.

Meet the experts: W. Christopher Winter, MD, is a neurologist and sleep medicine physician with Charlottesville Neurology and Sleep Medicine in Virginia and host of the Sleep Unplugged podcast. Jessica Cording, RD, is author of The Little Book of Game-Changers. Keri Gans, RD, is author of The Small Change Diet.

What’s *not* normal is feeling wiped after every single meal you have, says Jessica Cording, RD, a New York City-based nutritionist and author of The Little Book of Game-Changers. “It really comes down to what you eat and any underlying health conditions you may have,” she says.

Basically, there’s usually a reason why you feel tired after eating—and it may even be something you should look into with your health care provider. Let’s get into the top causes.

You ate a larger meal.

There’s a lot of chatter about feeling like you need to take a nap after big meal, and this phenomenon is for real, says Keri Gans, RD, a nutritionist in New York City and author of The Small Change Diet. There’s a chemical process at play that involves the amino acid tryptophan, the feel-good hormone serotonin, and melatonin, the hormone your brain produces that makes you feel sleepy, she says.

“Tryptophan is a precursor to serotonin and is naturally found in many foods we eat [and] serotonin is a precursor to melatonin in our bodies and can lead to sleepiness,” she says. “The larger the meal, the more melatonin is potentially produced.” And that can make you feel tired after eating more than you normally would. Now, while certain foods do contain more tryptophan (you’ve probably heard this about turkey) or melatonin (such as cherries) than others, the extreme sleep-inducing effects really come down to portion sizes in general.

You have hypoglycemia.

Hypoglycemia is what happens when the level of glucose (sugar) in your blood drops below what’s healthy for you, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) says. Hypoglycemia is common in people with type 1 diabetes and those who have type 2 diabetes but depend on insulin for blood sugar management, the NIDDK says.

Low blood glucose can make you feel shaky, dizzy, irritable, and tired, including after you eat, Cording says.

You drank alcohol with your food.

You’ve probably heard before that alcohol is a depressant. “It slows down the functioning of your brain and nervous system, which can result in drowsiness and fatigue,” Gans says.

As a result, if you have a glass of wine or cocktail with dinner, you may feel a little sleepier than you did before you ate, she says.

You’re dealing with insulin resistance.

Insulin is a hormone made by your pancreas that helps glucose in your blood get into your cells, where it’s used for energy, the NIDDK explains. When you have insulin resistance, the cells in your muscles, fat, and liver don’t respond well to insulin and can’t easily take in glucose from your blood.

“When you have insulin resistance, your body’s process of metabolizing glucose isn’t efficient,” Cording summarizes. Because of this, you can end up feeling tired, both after meals and during other times of the day.

You had a lot of carbs.

Carbohydrates can cause a spike in your blood sugar—and a crash if you don’t eat them with protein and fat to balance things out, Gans says. That can make you feel “overwhelmingly tired,” she says. So, PSA, make sure you’re pairing your carbs with other macros.

You’re not getting enough sleep.

When you feel tired, you may be more likely to eat to try to rev up your energy levels and stay awake, Dr. Winter says. “You may feel like you’re not hungry, but you’ll eat out of sleepiness to try to stimulate yourself,” he says. “A lot of times, those eating patterns are directed toward trying to keep you awake.”

Digesting food requires your body to work a little harder than usual, so you can end up feeling a little more tired after you eat than someone who has gotten more rest, Dr. Winter explains. Remember: Getting your seven to nine hours of sleep at night is the foundation of a healthy lifestyle.

You have obstructive sleep apnea.

Obstructive sleep apnea is a condition that causes you to stop and start breathing while you sleep, per the Mayo Clinic. That causes people to wake up frequently during the night and can lead to high levels of sleepiness during the day.

“Having a condition like obstructive sleep apnea increases your baseline level of sleepiness,” Dr. Winter says. “You’re already closer to wanting to fall asleep anyway, and eating can make you feel even more sleepy.”

How To Prevent And Treat Fatigue After Eating

If you find that you’re feeling tired after every time you eat, Cording says it’s a good idea to first take a look at what you’re eating. “You want to have a balance of protein, fat, and carbs,” she says. “Eating smaller, more frequent meals vs. larger meals is thought to be helpful as well.”

“The key is to try and consume well-balanced meals,” Gans says. She suggests focusing on filling your plate with 25 percent protein, 25 percent high-fiber carbohydrates (like barley, quinoa, or legumes), and 50 percent vegetables. “Also a serving of fat, for example, one tablespoon of olive oil or 1/4 of an avocado, should be included,” she says.

Cording also recommends keeping tabs on how full you feel as you eat. “If a 10 is Thanksgiving full, you want to check in with yourself at a seven or eight,” she says. “You want to feel like you’re not hungry after a meal, but you don’t want to be overly full.”

When To See A Doctor

If you’re suddenly feeling tired after meals and this wasn’t an issue for you before, Dr. Winter recommends that you check in with your doctor to see what could be going on.

That’s especially true if you’ve been sleeping well, eating a balanced diet, and limiting alcohol, and you’re still feeling wiped after you eat, Gans says. “It can’t hurt to discuss it with your physician,” she says.

Bottom line: It’s normal to feel a little tired after you eat here and there. But if you find it’s a regular thing for you, it’s a good idea to set an appointment with your doctor.