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Why do I Feel Tired After Eating?

Everyone has experienced it: that feeling of exhaustion and sleepiness after eating a meal. Whether it’s after Thanksgiving dinner, or just a regular meal, that post-meal tiredness has affected all of us at one time or another. Have you ever asked yourself why eating a meal is often followed by drowsiness, and the desire to rest?

Feeling a bit tired after a meal is completely normal, and it is generally not something you should be concerned about. Several factors contribute to the post-meal food coma, or in medical speak, postprandial somnolence. If you’d like to minimize the drowsy effects of post-meal sleepiness, there are some steps you can take, and the first step is taking some time to understand digestion.

How Digestion Works

Simply living and existing is energy-intensive. Whether you are constantly working out and exercising, or living a sedentary lifestyle, we all need energy to live. How do we get this energy? From food, of course.

Digestion is the biggest factor contributing to the tiredness felt after eating a meal. After all, your digestive system has a lot of work to do, especially after you eat a big meal. Knowing how digestion works will help you understand what is really going on after you finish a meal.

The Digestive Cycle

After you finish a meal, it takes about six to eight hours for food to pass through your stomach and small intestines. During this time, the digestive system breaks food down into glucose, which our bodies use as fuel. Macronutrients, like proteins, provide energy to our body through calories. In addition to our digestive cycles providing fuel and energy to our bodies, the digestive cycle triggers a number of other responses in our bodies.

To create the feeling of fullness, our bodies release hormones like amylin, glucagon, cholecystokinin (CCK). Also, as we digest, our blood sugar rises, and in response, insulin is produced. Insulin allows the sugar in our blood to be taken up by our cells to be used as energy.

The Parasympathetic Nervous System

All of these digestive processes are carried out by the parasympathetic nervous system. The parasympathetic nervous system is involuntary, meaning that it operates without you knowing it. It is responsible for both sleep and digestion, which is why it is sometimes referred to as the “rest and digest” function.

While digesting, our parasympathetic nervous systems assume we are in a state of rest. During digestion, more blood is sent to the digestive system. Normally, the digestive system receives about 20%-25% of our blood pumped from the heart; however, during digestion, the amount of blood flow sent to the system can almost double.

Why is Digestion Important?

It is no wonder why digestion is so important: it provides our bodies with the fuel and energy we need to live. And, digestion is no easy task. After we eat a meal, our digestive system is hard at work, turning that food into fuel and energy, releasing our hormones, regulating chemicals in the blood and cells (like sugar), and pushing that food onwards to the GI tract.

Reasons You Feel Tired After Eating

So we’ve discussed how the digestive cycle works, and why it’s important. Now we can get into specific reasons that this process may make us feel tired.

Drops in Blood Sugar

Eating foods that cause your blood sugar to drop can help reinforce the tired feeling after eating. After you eat a meal, food is broken down into glucose (sugar), and transported to the blood where it can then be distributed to cells with insulin. Eating some foods, like carbohydrates, increase your blood sugar rapidly, and then quickly drops off, leaving you feeling tired.

Circadian Rhythm

The circadian rhythm is a 24-hour internal process that regulates the sleep and wake cycle. It is also thought of as the body's internal clock. Studies show that eating may affect the circadian rhythm because “human molecular clocks may be regulated by feeding time and could underpin plasma glucose changes”. In other words, meal timing is very important, because eating at different times of the day can adjust the circadian rhythms of individual cells and tissues, leading to tiredness.

Additionally, humans typically get drowsy around 2-3 pm, usually after eating lunch. This is a natural part of our circadian rhythm that corresponds with alertness, sleepiness, and attention span.

Lack of Quality Sleep

If you are not rested, the tiredness that follows after eating a meal may increase. After you eat, you are more likely to feel full and rested, and if you did not get quality sleep recently, then you are more likely to feel tired after eating a meal. Therefore, if you got a poor night’s sleep before eating a meal, you may be even more tired after eating.

Sleep Disorders

Sleep disorders are another reason that may be causing you to feel extra tired after eating. These can include:

  • Sleep Apnea. A breathing disorder characterized by disruptions in breathing.
  • An inability to stay awake during the day, usually associated with chronic daytime sleepiness.
  • A difficulty falling and staying asleep.
  • Restless Legs Syndrome (RLS). Characterized by a tingling sensation in the legs, discomfort in the muscles of the leg, and a desire to move and stretch them.
  • Circadian Rhythm Disorder. A disorder related to general problems in the circadian (sleep-wake cycle). Generally involves trouble falling asleep, and waking up at the right/desired times.

If you are affected by any of these sleep disorders, it could seriously be affecting your quality of sleep, how much sleep you get, and therefore your daytime alertness and energy. If you are affected by any of these sleep disorders, that may be a powerful contributing factor, resulting in your chronic post-meal fatigue.


Drinking alcohol during a meal can make you feel significantly more tired. Alcohol is a nervous system depressant, meaning that it has a sedative effect, making you relaxed and drowsy. Furthermore, drinking alcohol negatively impacts your quality of sleep.

Quantity of Food Eaten

Eating large amounts of food may worsen sleepiness after a meal. For example, you are more likely to feel tired in the afternoon if you have a large lunch. Eating causes our blood sugar to rise and then drop, resulting in tiredness, so if you eat more, your blood sugar may rise more to accommodate the amount of food consumed, and therefore there will be a larger drop. Additionally, larger meals are more work for your digestive system to handle, and require more blood and energy to process.


Although the digestive system processes all food in the same manner, different foods can affect your body in different ways, due to the varying composition of many foods.

One commonly cited example of certain foods making you sleepy is turkey. Turkey contains a chemical called L-tryptophan, one of nine essential amino acids. When tryptophan crosses the blood-brain barrier, it stimulates the production of serotonin and melatonin. Melatonin is known as the “sleep chemical”. It is an important factor in the Circadian Rhythm and sleep. Serotonin is a neurotransmitter that helps to regulate sleep. So, it is no wonder that tryptophan is connected to after eating a large amount of turkey, because of its connection to melatonin and serotonin, two sleep-related chemicals.

In the United States, Thanksgiving dinner is commonly served with turkey being the main course. After eating the turkey-centric meal, people often feel this sudden tiredness and urge to sleep, sometimes contributing this feeling to a large amount of turkey they’ve eaten, and therefore tryptophan in the bloodstream. However, the idea that tryptophan directly leads to this sensation is mostly a myth.

Tryptophan cannot freely circulate in the brain, because it is unable to pass the blood-brain barrier on its own, instead, it has to enter by hitching onto a transport protein to enter the brain. Other amino acids use the same tactic to break through the blood-brain barrier, and there are many of them that are competing to get access into the brain. Therefore, very little tryptophan is able to get into the brain, where it can produce melatonin and serotonin. However, it is important to note that tryptophan can be stored in the body, and released when you eat carbohydrates.

The reason you feel sleepy after a Thanksgiving meal is likely due to other factors. For example, as we discussed above, the quantity of food eaten is a factor, along with the consumption of alcohol and carbohydrates.

Carbohydrates are also a factor in your diet that may be causing the sleepy feeling after eating a meal. As we discussed above, sudden drops in blood sugar can trigger drowsiness, and eating carbohydrates does just that: they cause a sudden spike in blood sugar, followed by a quick drop.

There are many other foods that may cause you to feel sleepy after a meal. For example, cherries affect levels of melatonin, bananas help your muscles relax, and like carbohydrates, foods high in protein may contribute to sleepiness as well.

Sedentary Lifestyle

Regular activity and exercise help to boost energy and reduce fatigue. Exercise may help to increase your levels of energy, and reduce the effects of post-meal fatigue. On the other hand, being sedentary reduces your overall energy (and stores of energy), resulting in increased exhaustion and tiredness after meals.

Food Allergies or Intolerances

Food allergies may be contributing to the problem, too. Any foods that you are allergic or sensitive/intolerant to can contribute to fatigue after eating them. When you are allergic to a food, and consume it, your body releases histamines, causing daytime sleepiness. Food sensitivities and allergies can cause physical exhaustion, mental fatigue, and/or an upset stomach. 

Seasonal Allergies

Seasonal allergies can contribute to daytime sleepiness and chronic fatigue just as food allergies do. Like food allergies, seasonal allergies release histamines in the body when you are exposed to the allergen, leaving you feeling mentally and/or physically tired.

Health and Medical Conditions

Several health conditions can play a factor in feeling tired after eating.

Diabetes. Diabetes is a common reason for feeling tired after a meal. Diabetes affects your body's ability to produce insulin, which allows for the transfer of energy (sugar) from your blood to cells. When someone is affected with diabetes, their ability to produce insulin is very low or non-existent, resulting in fatigue. This is because the energy your body needs to function is unable to be transferred to the cells that need it to function.

Underactive thyroid. When you have an underactive thyroid, or hypothyroidism,your thyroid is unable to produce enough thyroid hormones. The thyroid is responsible for delivering energy to the organs in the body, and also helps the heartbeat and the digestive system work. Therefore, it is no surprise that a common symptom of hypothyroidism is fatigue.

Celiacs disease. Celiac disease damages the villi in the small intestine that help you to absorb vitamins, minerals, and nutrients. Celiac disease leaves those affected by it chronically fatigued (along with other symptoms) when they consume barley, wheat, and rye, which they are unable to digest.

Anemia. Anemia is a common cause of fatigue for many people around the world. Anemia is a condition where you do not have enough red blood cells, resulting in chronic fatigue.    

Mental Conditions

Mental conditions may also contribute to chronic drowsiness after eating. Depression and anxiety are two very common mental disorders that can leave those affected by them feeling chronically tired.

Diagnosing Tiredness After Eating

  • Keep a food diary. Keeping a food journal is a good way to diagnose the reason your tired after eating if it has to do with the types of food you’re eating, the times you’re eating, or the quantity of food. Before you eat a meal, note the ingredients, quantity, and time of the meal in a notebook. Then when you’re finished, write a couple of sentences about how tired you feel. Doing this over a few weeks may help you narrow down the cause of the problem.
  • See a doctor and get tests. If you have no luck with a food diary, try seeing your doctor. They’ll ask you relevant questions about your diet and symptoms, and conduct tests to help you diagnose the problem. Common tests that the doctor might conduct for you include:
    • A1C or hemoglobin test. A1C tests measure average blood glucose over a period of two to three months. This test is mainly used to determine if a patient has diabetes, which may be the cause of fatigue.
    • Blood glucose test. This test measures the amount of sugar in the blood. This test is also commonly used to diagnose diabetes.
    • Food allergies tests. Food allergy tests involve testing your blood, or pricking your skin with a variety of possible allergens, to see if you have any reaction. If you do have any reactions, the skin allergy tests will let you know.
    • An elimination diet. This may also be used to diagnose any sensitivity or allergies to food. The elimination diet is when you eliminate certain foods from your diet to see if you have any positive changes (in this case) in fatigue or energy levels.

Tips to Stop Feeling Tired After Eating

  • Drink water. Drinking plenty of water will prevent you from getting dehydrated, and feeling the post meal slump.
  • Exercise / Take a walk. As mentioned above, exercising regularly boosts energy, and reduces fatigue during the day. Plus, it may make it easier to fall asleep, and get quality sleep at night.
  • Get quality sleep. Getting quality sleep every night is a great way to address post-meal sleepiness. Try falling asleep at the same time every night, and waking up at the same time every day. This will get your circadian rhythm into a routine, and make falling and waking up at the right time both easier and more restful. Other ways to ensure you get quality sleep are by improving your sleep environment, and reducing alcohol and caffeine consumption.

Improving your sleep environment includes making sure you are sleeping in a cool environment, so you don’t overheat, along with reducing any noise that may keep you up at night. One great way to remedy a noisy sleep environment is by playing ambient music, or white noise, while you sleep.

Another effective way to improve your sleep environment is making sure you have the right mattress. Sleeping in a mattress that doesn’t fit your needs can leave you with day-time fatigue and an inability to get the rest you need. If you think you need to get a new mattress, check out Latex For Less for affordable and comfortable latex mattresses.

  • Reduce alcohol and caffeine consumption. Unfortunately, both alcohol and caffeine negatively impact our quality of sleep. Reducing the amount of alcohol we drink before bed, and cutting back on caffeine during the day may improve sleep. Try to avoid consuming any caffeine in the afternoon if you have trouble falling asleep at night.
  • Eat smaller meals often. Eating smaller meals often, rather than eating a few, larger meals can help reduce sleepiness after meals. As mentioned earlier, eating a large quantity of food can make you feel more tired. Eating smaller meals more often is easier on your digestive system, and should result in a smaller spike and drop in blood sugar.
  • Changing your diet. Eating healthy foods and balanced meals, especially ones that are good for your gut, may fix the problem. Try eating complex, high-fiber carbohydrates, along with healthy fats, and cut out any fast foods that will cause a spike in blood sugar, and a quick crash to low blood sugar. Also, including extra virgin olive oil in your diet may help you if you experience insomnia.
  • Get outdoors or use bright light therapy. Getting outside and being exposed to bright light and sunlight will increase your vitamin D levels, and may also boost your energy and reduce post-meal sleepiness.
  • See a therapist. If you believe your depression and/or anxiety is the root of your tiredness, it may benefit you to seek professional help. Therefore, seeking help from a therapist, for example, may reduce your anxiety/depression, and by proxy, reduce your fatigue.

When to See a Doctor

Having a slight dip in energy after eating a meal is natural. However, being chronically fatigued or tired after eating a meal may signal another problem. If you have any of these problems listed below, you should consult your healthcare professional:

  • Blood glucose problems. Blood glucose problems are a warning sign of a more serious problem, often Diabetes. Seeing a doctor is the best way to remedy this issue.
  • Chronic lack of sleep. Chronic lack of may also be a warning sign of a greater problem. For example, you could be affected by Sleep Apnea, insomnia, hypersomnia, narcolepsy, Circadian Rhythm Disorder, or another disorder you are unaware of. If you find yourself chronically fatigued and unable to sleep, you should speak to your primary care physician.
  • Food allergies. Food allergies can be a serious problem. They can cause digestive issues, diarrhea, discomfort, fatigue, and may affect your quality of sleep. Quickly diagnosing any food intolerances or allergies, and eliminating them from your diet, should fix the problem, and get you healthy and full of energy again.

Elizabeth Magill

Elizabeth Magill is a professional freelance writer and editor who holds an MBA. Liz specializes in writing about health news, medical conditions, healthy living, small business, career and work, personal finance, and green-living, including news and trending topics in these specialties. Her clients include Healthline, The Motley Fool, GoBanking Rates,, Big Interview, HealthNews, Intuit Small Business Blog, Intuit Health, American News Report,, IFX Medical, and many others. She’s also a published eBook author and ghost writer for various clients in the health, medical, career, small business, and personal finance niches.