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Jul 2, 2024 · If you've ever had a food coma, then you know that sleepy feeling. But why do they happen? A doctor answers your questions, including how to prevent them.
Rich desserts—such as cheesecake, chocolate mousse, and ice cream sundaes—have a similar effect. This is due to the release of CCK, which slows down the digestive process.
- Overview
- What is a food coma?
- What causes a food coma?
- How long does a food coma last?
- Is a food coma harmful?
- How to prevent a food coma
- The bottom line
If you feel sleepy after chowing down, you may wonder what’s going on.
This experience is particularly common after large meals, such as those common on Christmas or Thanksgiving. It’s often referred to colloquially as a food coma. Medically, it’s called postprandial somnolence, which just means sleepiness after eating.
Although there’s limited scientific evidence about how or why this sleepiness occurs, theories exist.
This article tells you what food coma is, the main theories on what causes it, whether it’s dangerous, and how to avoid it.
Keep in mind
Postprandial somnolence — the medical term for food comas, or post-meal sleepiness — isn’t well defined. As many studies on this phenomenon are from the early 2000s, more research is needed.
Postprandial somnolence, or a food coma, is the feeling of tiredness after eating a meal.
It’s also commonly known as the “post-lunch dip,” as many people notice the effects in the early afternoon following lunch (1).
You may experience the following symptoms:
•sleepiness
•lethargy
•physical exhaustion
Changes in blood circulation
For a long time, food comas were thought to be triggered by an increase in blood flow to your gut causing a reduction in blood flow to your brain (2). Yet, this theory has been challenged. Your body is able to maintain blood flow to your brain in many types of stressful situations, such as during exercise, when your muscles require more blood (2). So, it’s unlikely that blood flow to your intestines diverts enough blood to cause sleepiness. In fact, an older study suggests that blood flow to your brain may increase following meals (3). While a more recent, small study found a decrease in blood flow to the brain following lunch, this effect was only seen in people who skipped breakfast. This study also didn’t link the decrease in blood flow to feelings of tiredness (4).
Eating a big meal
People often complain of food comas after eating large or heavy meals. Studies in fruit flies found that larger meals — particularly those high in protein and salt — resulted in longer post-meal sleep (5). In a study in men who ate pizza, those who overate reported less energy and more physical tiredness, sleepiness, and lethargy in the 4 hours after eating, while those who ate only until comfortably full had no adverse effects (6). Another older, small study compared the effects of a light lunch with a heavy lunch that had 3 times the calories on driving and sleepiness. The heavy lunch increased the number of times drivers deviated from their lane, and the effects increased over a 2-hour period (7). These studies all suggest that large meals may be a trigger for postprandial somnolence.
Meals high in carbs, fat, or protein
Meals rich in carbs, fat, and protein have all been linked to food comas (8). These macronutrients may promote sleepiness independently through various mechanisms. They may also influence each other. For example, high carb meals may raise levels of the amino acid tryptophan in your blood, which increases the amount of serotonin — a hormone linked to sleep — in your brain (9, 10). Furthermore, meals high in protein may also induce sleep if they contain foods with high amounts of tryptophan. These foods include chicken, eggs, cheese, fish, turkey, milk, and tofu (11). In combination, calorie dense, high fat, high carb meals cause the release of small proteins known as cytokines, which are linked to fatigue (12). Additionally, meals high in fat or protein may raise levels of peptide YY and the hormone cholecystokinin, both of which may increase feelings of sleepiness (10). Still, the relationship between foods and released hormones, neuropeptides, inflammatory proteins, and other substances is complex. Determining which, if any, may be responsible for sleepiness requires more research (8).
No studies have specifically examined how long food comas last.
However, some research notes that the aftereffects have lasted as long as 4 hours after a large meal (7).
This is supported by anecdotal reports of people feeling tired up to a few hours after eating.
Keep in mind that the length and severity of your exhaustion may also be affected by other factors, such as a poor night’s sleep or drinking alcohol (7, 18).
Summary
While limited scientific data exists on the duration of food comas, increased sleepiness after eating may last several hours.
Although scientists don’t yet fully understand what causes a food coma, all proposed theories involve your body’s natural physiological responses or processes.
Feeling a little tired after eating is common and no cause for concern — though tiredness can be dangerous in some situations, such as driving or operating heavy machinery (7).
Although sleepiness after a meal is quite typical, it may be inconvenient when you need to work or study — and even dangerous if you need to drive or perform risky activities.
You can counteract or prevent food comas by following these tips:
•Eat modest portions. Eating large portions is linked to sleepiness, so keep portions moderate and be mindful of your fullness levels (7).
•Choose balanced meals. A study of Brazilian truck drivers found that those who ate a diet low in animal fats, processed foods, and alcohol experienced less sleepiness while driving than those with unhealthy diets (24).
•Limit alcohol intake. Alcohol may induce sleep and disrupt nighttime sleep, causing daytime tiredness. If you drink alcohol with your meal, you may feel sleepier (18).
•Stay hydrated. Dehydration may cause tiredness and impair your mental function, so ensure you drink plenty of fluids — including water, tea, and dairy and nondairy milks — throughout the day (25, 26).
Feeling sleepy after a meal is a common phenomenon known as a food coma.
While research is ongoing, this condition may be caused by sleep-inducing hormones, eating large meals, your body’s internal clock, and evolutionary adaptations.
A food coma isn’t unhealthy, but it may be inconvenient when you need to work or study and potentially dangerous when you’re in high risk situations, like driving.
You can take simple measures to avoid food comas, including limiting portion sizes, choosing more balanced meals, limiting alcohol intake, staying hydrated, getting enough sleep, using bright lights, or just taking a nap.
Aug 23, 2018 · At most, a coma lasts for a few days or weeks. As soon as patients open their eyes, they are said to “awaken” from the coma. This does not, however, mean that a person is conscious.
Dec 17, 2019 · Yes, food coma (also known as postprandial somnolence) is a real thing, with science to back it up. Here, learn all about this phenomenon, the foods most likely to cause it, and what you can do to prevent one this holiday season.
May 25, 2024 · In some situations, a medically induced coma may help prevent brain damage, improving the chances of survival and reducing the likelihood of long-term disability. This article describes the causes of coma, rating scales, and what to expect if your loved one has been diagnosed with a coma.
People also ask
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