Do you often feel tired after eating, especially lunch? Or perhaps you feel that drowsy sensation sneaking in after a calorie-dense meal? If so, you’re not alone.

Many people experience something like whole-body sleepiness kicking in after eating a large meal. For the most part, this is considered quite normal, although not pleasant, especially if you’re in the middle of your workday.

Why Do People Feel Tired After Eating?

There are different theories about why this happens, with some falling on the meal composition, while others review the meals’ timing or the body’s circadian rhythm.

So, here’s a look at some of the most common reasons why you may get tired after eating.

The Type of Food

Nutrition is not only about calories in vs. calories out, but more about the nutrients that you consume. Here, certain foods are believed to trigger sleepiness more than others. For instance, foods rich in protein and carbs are common culprits.

Protein and Sleepiness

The relationship between food and how the body processes it works on multi-levels. But for starters, the body needs the energy to function, and food provides just that by being broken down into fuel.

However, food doesn’t simply get changed into energy, but digestion also triggers many responses within the body.

One of these is the release of certain hormones. Some hormones increase the sense of satiety, whereas others can bring on drowsiness.

Protein and carbs paired with healthy fats make the ideal platter for everyone. But when you start feeling sleepy after eating, this otherwise dynamic duo may have something to do with it.

With regards to protein, protein-dense foods often contain an essential amino acid called tryptophan. [1]

Tryptophan helps the body produce serotonin which is a chemical that regulates mood and sleep cycles.

Serotonin has a calming effect, which is great if you’re looking to unwind at the end of the day but isn’t ideal when you’re in the middle of doing work that requires a good level of concentration.

Eating a meal rich in protein is seen as making an individual feel sleepy and causing the infamous post-meal haze.

Of course, this is not a cause in isolation, and other factors also come into play. But it is something that could be making you feel lethargic right after you eat.

feeling weak and tired after eating

Carbs and Sleepiness

Carbs, on the other hand, are seen as the first source of fuel for the body. So, how does this food group play into the “feeling very tired after eating” equation?

Well, there are two types of carbs to consider. First are the complex carbs found in whole foods such as whole grains, starchy and non-starchy vegetables, and beans and legumes.

These carbs take their time being digested and thus provide the body with a steady supply of energy. There are no spikes and lulls involved when you consume complex carbs.

Plus, these foods are also excellent sources of fiber, and fiber keeps blood sugar levels in check from spiking too high.

The second type is known as simple carbs, which get digested pretty much instantly. These are processed in the small intestine from where they pass onto the bloodstream to be used for energy.

Now, it’s true that sugar gives you an instant energy pickup. But, being the simple carb that it is, sugar may equally be a sedative since its aftereffects are way stronger than the little initial kick you feel first.

On one front, high sugar consumption inhibits the production of Orexin, which is a brain chemical that stimulates the feeling of being awake. So, the more sugar you consume, the sleepier you start to feel.

On another front, sugar consumption also spikes your blood sugar into a wild roller coaster ride. And eventually, what goes up must come back down, and it comes down in a hard blood sugar crash. [2]

This roller coaster can be addicting to the body, as it starts to depend on the quick fix of sugar to have more energy, ultimately leading to more crashing. And before you realize it, the whole thing turns into a vicious cycle, which is hard to break away from.

The Size of The Meal

Another theory investigates the connection between how much food an individual eats and feeling tired.

Typically, larger meals are linked to making people feel fatigued after eating. Research on the topic shows that people who consume larger lunches experience more of an afternoon slump than those who eat less at midday.

The reason given behind this is that the body has to work harder and use up more energy to break down food.

This includes both the brain and the intestines working overtime, which demands more than their regular share of energy reserves to be effective.

When someone has a large meal, the brain redirects energy towards digestion, which involves sending blood cells to the small intestine to help break down food and carry nutrients to the rest of the body.

The intestines, on their part, also work harder to metabolize the heavy meal just eaten while the rest of the body eases and relaxes.

The overall effect is seen as feeling lethargic since the brain diverted the energy towards digestion and didn’t have as many blood cells to help it function.

The Timing of The Meal

Finally, an individual’s circadian rhythm or natural body clock may also factor in how they feel after eating.

Research shows that people naturally have a lull in energy at 2 am and then again at about 2 pm, which explains Spain’s typical siesta and riposo in Italy.

It may also well be why the upcoming trend of Silicon Valley Sleepers was sleeping on the job is being embraced by some of the USA’s biggest employers, including Google.

But coming back to when to eat, a consistent eating schedule should also sync with circadian rhythms. Consuming meals and snacks at the right time can help keep the digestive system in top shape. [3]

When a person fails to eat consistently every day, their stomach ends up overworking, which can trigger indigestion and bloating. However, eating on a schedule allows proper digestion, sustains energy throughout the day, and minimizes unwanted cravings.

On the other hand, skipping meals just because you’re not hungry or don’t have time can lead to sugar cravings in the evening, eating comfort foods to make up for lost energy, and feeling irritated and tired at the same time.

The key is to eat tiny portions every 3-4 hours to give the stomach enough time to digest its contents properly.

By setting specific times for breakfast, lunch, dinner, and snacks, the body knows exactly when to eat, preventing overeating and improving digestive health. And since people are creatures of habit, once you develop a healthy eating routine, you will sustain your energy levels throughout the day.

Other Reasons that Cause Fatigue after Eating

Some other non-food-related factors that may be causing you to feel sleepy after eating can be traced to one or more of your habits or routines. Some of these include the following:

feeling extremely tired after eating

Poor Sleeping Habits

Not getting enough sleep at night can have effects that spill over into how you feel after a meal. Sleep-related fatigue can manifest both as physical and mental fatigue.

It can become physically challenging for the former type to do things that are otherwise not a problem, and people can experience muscle weakness.

For the latter type, it becomes difficult to concentrate on things and stay on task. A person may feel sleepy or have a hard time staying awake while working.

If you’re already suffering from sleep-related fatigue or sleep deprivation, having a full meal has the effect of relaxing the mind and body, and you may feel even more like resting. This can, once again, translate into feeling sluggish after eating. [4]

The pattern can become more noticeable, especially if you haven’t been sleeping well at night repeatedly.

Sometimes, a quick power nap can help, but you need to optimize your sleep habits for long-term results.

The Level of Physical Activity

Lethargy often becomes a part of your day when the body isn’t active. Even simple tasks like walking up a flight of stairs can get your heart pounding if all you do is spend your day sitting at a desk.

Sitting like a statue at your desk can make you feel like nodding off since the body associates stillness with going to sleep.

Typically, the more active a person is, the more energy they have during the day. Part of this comes from endorphins, which the brain produces when a person exercises.

Endorphins are feel-good chemicals that activate the brain’s happy side and keep things alert and in focus.

Adding in some physical activity to your day will temporarily boost alertness and energy levels. Even short bursts can work their magic and help you counter the midday slump effects after lunch. [5]

When fatigue is not resolved by getting enough sleep, physical activity, good nutrition, or a low-stress environment, a doctor should evaluate it.

Other Health Conditions

If fatigue after eating refuses to subside and starts to affect the quality of life, it may be time to get a professional’s opinion.

Certain medical conditions may be aggravating the issue and causing excessive tiredness after eating.

Food Intolerances or Allergies

Food intolerances or allergies may leave you feeling tired after meals. Since an allergy or intolerance can impact digestion, it may cause other symptoms like headaches or gastrointestinal discomfort, which can drain energy levels.

Among these, celiac disease is a condition where the body has a gluten intolerance. This can encompass both gluten allergies and sensitivities.

The lining of the small intestine becomes damaged and is unable to absorb nutrients properly. This can result in malabsorption and eventual nutrient deficiencies.

Over time, these deficiencies become more severe and may manifest as a constant state of feeling fatigued.

Gluten-related fatigue is often debilitating and long-lasting.

A sub-type of the condition known as the silent celiac disease often presents no direct symptoms of being linked to the digestive tract. Instead, people experience other symptoms such as fatigue, insomnia, irritability, and brain fog, to name a few.


Anemia, or more particularly, iron deficiency anemia, is when there is insufficient iron in the body.

Those with mild to moderate iron-deficiency anemia may not present any symptoms, while more severe cases can cause fatigue and lethargy, among other symptoms.

Symptoms generally worsen as the condition becomes more severe and, if left untreated, may even become life-threatening.


Diabetes is of particular concern as it could manifest as either hyperglycemia or hypoglycemia.

With hyperglycemia or high blood sugar, post-meal tiredness may be aggravated by a high sugar consumption level. With inefficient or insufficient insulin to transport sugar to the cells for energy, you may be left feeling tired.

Hypoglycemia, where blood glucose levels are low, can have you feeling tired after consuming simple carbs that get digested quickly. The instant digestion spikes up sugar levels that then crash in a short amount of time.

The crash may leave you feeling tired and sleepy, along with other symptoms such as weakness or dizziness, irritability, hunger, and even confusion.

Both hyper and hypoglycemia are severe medical conditions, especially for diabetic individuals, and should be addressed immediately with professional help.

How to Stop Feeling Tired After Eating?

Feeling tired after a meal can be frustrating, especially at midday when you may need to be alert.

Some strategies that may help ward off tiredness or at least minimize the drowsiness after a meal can include the following suggestions:

Don’t Skip breakfast?

Having a hearty breakfast at the start of the day is a great way to keep energy levels up later on in the day.

But this does not include a cup of coffee on the run or a candy bar from the vending machine. Yes, you will get the instant jolt of sugar and caffeine to get you started, but it won’t deliver the long-term fuel to keep you running for the rest of the day.

Skipping breakfast only compromises your energy standards for the rest of the day, so, at lunchtime, you feel overly hungry and become more vulnerable to making poorer food choices or eat up a larger portion.

On the other hand, you can try intermittent fasting. By regularly fasting, your metabolism may adapt, and ultimately, you might have even more energy than when you eat breakfast.

Well, experiment a bit and see what works best for you.

Eat Smaller Portions More Frequently

Larger meals require more energy for digestion, so instead of eating big meals, it’s recommended to consume smaller and more frequent meals and snacks during the day to sustain your energy levels. This practice can help your blood glucose levels stay steady and keep the body fueled for longer.

At the same time, try to watch what you eat, opting for foods like vegetables, whole grains, and healthy fats, which will keep your energy levels up.

Get Quality Night-Time Sleep

People who get enough sleep at night are less likely to experience a significant energy dip after lunch.

Simple strategies to improve your sleep patterns are reducing your caffeine intake, avoiding heavy meals at night, and limiting your alcohol consumption.

You can also try to be physically more active and maintain a regular sleep schedule by going to bed and waking up at the same time every day.

Get Some Exercise

Other than getting a good night’s sleep, exercising may also help keep post-meal fatigue at bay. Many studies show that regular exercise helps increase energy levels and reduce energy slumps during the day.

Even light exercise during the day, and especially after eating, can help minimize fatigue. Take a brisk walk to re-energize or do some squats and lunges. Anything that gets you breathing a little quicker and moving your muscles will do the trick.

Watch Your Drinking Habits

This refers to alcohol consumption and keeping yourself appropriately hydrated by drinking water and consuming electrolytes.

It is often the sensation of thirst and not so much hunger that makes you feel like you want to eat something. Since thirst precedes hunger, make sure to keep your body adequately hydrated.

Inadequate hydration also presents common symptoms such as headaches, which can cause you to feel tired excessively.

As for alcohol consumption, avoid drinking alcohol with meals. Another thing to consider is to modulate caffeine consumption, as this can also interfere with your regular sleep cycle.

Instead, opt for unsweetened tea or sparkling water that are both refreshing beverages but won’t add extra calories.

Take Energy-Boosting Supplements

Last but not least, taking energy-boosting supplements can quickly restore your energy after a meal.