Eating

Food Coma? Here's Why You Get Sleepy After You Eat

"I can't believe I ate the whole thing!" That's how it starts. How it ends: a nap on the couch, or at least a very unproductive afternoon. In everyday language, it's known as a food coma, carb coma, or the itis. In scientific terms, it's called postprandial somnolence ("postprandial" means after a meal, "somnolence" means drowsiness. Scientists are so fancy). But why does it happen?

Dig In

To understand the answer, it's important to know what happens in your digestive system when you eat. While you're chewing, your stomach produces the hormone gastrin, which triggers the production of the digestive juices that begin to break down your food. That broken-down food then moves into the small intestine as the gut releases the blood-flow regulating hormone enterogastrone. Meanwhile, your pancreas releases insulin to help your stomach absorb glucose from the carbohydrates in the meal. At the same time, insulin sends a variety of amino acids into the brain, including the infamous sleepy chemical known as tryptophan.

You might notice that food comas don't happen after every meal—just the indulgent ones. There are a few reasons for this: a meal high in carbohydrates triggers a larger spike in insulin, which makes more tryptophan enter your brain. When that happens, the tryptophan first turns into seratonin, which makes you feel good, and then into melatonin, which makes you feel drowsy. Glucose from the carbs also may block brain cells called orexin neurons, which are responsible for keeping you awake and alert.

Separating Meal Myth from Feast Fact

It should be mentioned, however, that when you combine tryptophan with all the other amino acids, hormones, and macronutrients you get in a meal, it doesn't have much of an effect. Stop blaming the Thanksgiving turkey! It has less tryptophan than chicken, anyway. Plus, high-protein meals don't have the same sleepy effect, since protein tends to promote the release of more stimulating amino acids.

Food comas are sometimes unavoidable—nobody wants to watch their diet during a holiday feast—but if you want to reduce your chances of nodding off after dinner, there are a few ways to do so. Watch your portions and eat slowly so your body's hormones have time to balance out. Also, make sure you're eating a balanced meal without too much starch or fat and with enough veggies and vitamins.

How Do Food Comas Work?

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Does The Tryptophan In Turkey Make You Drowsy?

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Key Facts In This Video

  1. It is a myth that the tryptophan in turkey is what makes people drowsy after Thanksgiving dinner. 00:21

  2. Tryptophan levels in turkey are actually lower than those found in chicken. 01:06

  3. Drowsiness after eating Thanksgiving dinner is caused by an overload of carbohydrates. 01:26

Written by Ashley Hamer November 19, 2016 / Updated: December 21, 2017