What Exactly Is a Food Coma, and What Causes It? We Asked Dietitians
Food comas are a common experience—here's what can trigger them (and how to prevent them).
Medically reviewed by Jessica Levinson, MS, RDN, CDN
Many of us know what it’s like to dig into a delicious holiday dinner or takeout meal, only to find ourselves drowsy or full-on snoozing on the couch shortly afterward. It's so common, in fact, that taking a nap after a big feast (like Thanksgiving dinner, for example) has become something of a tradition. This post-meal sleepiness is a classic example of the so-called "food coma"—or, in medical terms, postprandial somnolence.
The good news is that food comas are not a cause for concern, as uncomfortable as they may be. In fact, they’re pretty common, especially after eating a large meal.
But what is a food coma, exactly, and what’s going on in the body when you experience one? We asked registered dietitians for the 101 on food coma symptoms and causes, plus tips for preventing them in the first place.
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What Is a Food Coma, and How Does It Work?
A food coma refers to the feeling of fatigue after eating a meal, usually one that's large and rich. It’s a real thing—meaning there’s a scientific explanation behind the sensation. However, it does not involve being in an actual medical coma where you’re in a state of deep unconsciousness, says Kristen Carli, MS, RD, registered dietitian nutritionist and founder of Camelback Nutrition Wellness.
It won’t change your mental status and require a trip to the hospital, she explains, but instead, a food coma causes extreme tiredness and lethargy that can trigger a deep sleep. Much of this has to do with the natural digestion process, according to Carli. “When you eat a large meal, your body directs a significant amount of blood flow to the digestive system to break down the food,” she explains. “This diverts blood away from other systems, including the brain, which can lead to lethargy.”
The actual nutrients in food—most notably, carbohydrates and fats—also play a role in causing a food coma. For starters: “A large meal, especially one high in carbohydrates, can lead to a rapid spike in blood sugar levels,” Carli says. This often follows with a blood sugar crash, causing feelings of extreme tiredness.
Meanwhile, after eating a high-fat meal, your body releases hormones such as cholecystokinin (CCK), she adds. “CCK [regulates] appetite and digestion. It slows down the movement of food from the stomach to the small intestine, prolonging the digestion process,” she explains. “This hormonal response can contribute to feelings of sluggishness and lethargy.”
What’s more, carbohydrates and fats can cause a cascade of chemical reactions that may lead to that all-consuming food coma feeling. “When [you eat] a meal that’s rich in carbs and fats, it can trigger a release of insulin,” explains Valerie Agyeman, RD, registered dietitian and host of women’s health podcast, Flourish Heights. Insulin is a hormone that moves glucose, or sugar, from the bloodstream and into cells for energy, Carli says. This increases the production of tryptophan, an amino acid, in the brain. From there, tryptophan increases levels of serotonin, a neurotransmitter involved in mood and sleep. According to Agyeman, the heightened serotonin causes the body to relax and wind down, causing what’s called a food coma.
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Common Symptoms of a Food Coma
The symptoms of a food coma can vary from person to person, according to Agyeman. They can also range in severity, depending on the individual and meal. As Carli explains: “Some people might be more sensitive to certain foods or meal sizes, while others may not experience significant drowsiness [after eating the same food or meal].”
In general, common signs of food comas include:
Fullness
Sleepiness or drowsiness
Fatigue
Poor attention and concentration
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Foods and Eating Habits That Can Cause a Food Coma
It is possible to feel tired after eating almost any food, depending on your metabolism and habits (more on that below). However, certain foods have a higher chance of causing food coma symptoms, especially if they fit into more than one of the following categories.
High-Fat Foods
According to Carli, highly fatty foods like fast food meals (burgers, fries, and milkshakes) and deep-fried dishes (fried chicken, mozzarella sticks, and onion rings), are more likely to cause food comas. 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.
Related: 5 All-Star Foods That Are High in Healthy Fats
Refined Carbohydrates
Refined carbohydrates such as white pasta, white rice, and pizza (which typically has a white-flour-based crust) are common triggers of food comas, according to Carli. This is especially true for pizzas with thick crusts and heavy, high-fat toppings (like processed red meats), she notes.
High-Sugar Foods
The high sugar content of sweetened foods can cause blood sugar spikes, paving the way for an energy-sapping crash. Examples of sugar-sweetened foods include sodas and sugary beverages (like sports drinks and sweetened teas), candy, baked goods, breakfast cereals, ice cream, flavored yogurts, and chocolate milk with added sugar.
Related: These "Healthy" Foods Have Way More Sugar Than You Think
Foods With Tryptophan
As mentioned, insulin can promote the production of the amino acid tryptophan—but tryptophan is naturally found in some foods too. According to the University of Iowa, examples of foods with tryptophan include oats, honey, bananas, dairy products (like milk and cheese) and poultry, such as turkey.
Large Meals
Bigger meals, again, especially those high in carbohydrates and fats, are more likely to significantly impact blood flow, digestion, and the release of hormones and neurotransmitters that contribute to post-meal drowsiness, Carli says.
Related: 6 Healthy Foods That Boost Metabolism
How to Prevent a Food Coma
You don’t necessarily need to avoid all of the above foods entirely to prevent a post-meal slumber. With a more mindful approach to meals, it’s possible to enjoy these foods without dozing off immediately after eating them.
To prevent a food coma, consider these tips:
Eat smaller meals (avoid eating until you feel sick!). Compared to giant, super-filling meals, smaller, but still-satisfying meals place less strain on the digestive system, Agyeman says. They also provide your body with a steady source of energy, helping prevent blood sugar spikes and crashes.
Choose a mix of nutrients. Instead of noshing on only high-fat and/or high-carb foods, go for a more even mix of nutrients from a combination of food groups, including healthy fats (olive oil, nuts, avocado), fiber, and protein, Agyeman recommends. “This can help prevent food comas by stabilizing blood sugar levels and promoting steady energy throughout the day,” she says.
Stay hydrated. In case you need another reason to drink more water, it’s super helpful for supporting the digestive process. “It allows the body to break down food more efficiently and absorb nutrients effectively,” Carli explains. This can reduce the workload on the digestive system and prevent post-meal tiredness. Proper hydration also helps maintain stable blood sugar levels, reducing the risk of energy crashes, she says.
Practice mindful eating. According to Agyeman, mindful eating can help reduce stress and create a calmer atmosphere during meals, ultimately enhancing digestion and reducing discomfort after eating. This involves eating more slowly and with awareness, and checking in with your body’s satiety signals, which can help you avoid straining your system with a super-large meal that leaves you feeling sick and sluggish.
Take a walk. “Light physical activity, such as a short walk, may help improve blood flow and reduce the duration of the post-meal slump,” Carli says.
Related: Intuitive Eating Is a Happier and Healthier Way to Eat—Here's How to Begin
Do Food Comas Have Any Lasting Effects?
The sleepy haze of a food coma can, understandably, mess with your motivation and plans for the day or night. But fear not: Food comas are usually temporary, and they won’t have any long-term effects, Carli says. After all, a food coma is considered to be a normal physiological response to eating large, heavy meals, she notes. In other words, it happens! The symptoms will typically peak one or two hours after eating and last for a couple of hours, though it varies from person to person, she adds.
The exact duration of a food coma depends on several factors, including:
Meal size
Nutrient composition of the meal
Individual metabolism
Hydration status
If your symptoms do last longer than several hours—or if you continue to experience extreme sluggishness after eating—talk to your doctor. This may indicate underlying digestive issues, food sensitivities, or another concern, which will benefit from medical attention.
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Frequently Asked Questions
Are food comas normal?
It’s normal to experience a food coma after eating a large, rich meal. The fatigue and tiredness are caused by the natural digestion process.
Why do food comas happen?
After you eat a big meal, your body has to work extra hard to digest it. This can make you feel sleepy and fatigued. Large meals, especially those high in carbs and fats, can make your blood sugar spike and cause energy crashes. Plus, heavy meals can increase the production of serotonin, a neurotransmitter that makes you feel sleepy.
What are the signs of a food coma?
The symptoms of a food coma are different for each person, but common signs include bloating, fullness, sleepiness, fatigue, low energy levels, and difficulty concentrating.
How long does a food coma last?
For most people, symptoms of a food coma will peak after one or two hours and last for several hours. They are usually temporary and won’t have long-term effects. Factors like your metabolism, hydration status, and the type of food you ate will determine how long the food coma lasts.
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