Why do you feel sleepy after a heavy lunch?

Dristi Sharma
Dristi SharmaSep 15, 2023 | 08:00

Why do you feel sleepy after a heavy lunch?

There are various reasons that can influence post lunch sleepiness. GIF: dailyO

Do you also feel sleepy after having a heavy lunch? Do you find yourself struggling to stay awake while working or studying after eating, making it difficult to control your sleep, and craving that 10 to 15 minutes of a power nap? Well, you're not alone.

In fact, feeling sleepy after lunch is common for many people.

Here's why that happens

Dr Ankit Gupta, MBBS, and medicine director, Sumitra Hospital, Noida, explains that there are various reasons why one can feel sleepy after lunch. 


1. Circadian rhythm

Our body has a natural biological clock known as the circadian rhythm, which regulates our sleep-wake cycle. Typically, there is a natural dip in alertness and energy levels in the early afternoon, often referred to as the "afternoon slump". So, this dip is a normal part of our circadian rhythm and can make you feel sleepy.

2. Digestion

Another reason he says is digestion.

"After eating a meal, your body redirects blood flow to the digestive system to help process and absorb nutrients from the food. This diversion of blood can lead to a decrease in blood flow to the brain, which may result in feelings of drowsiness and reduced alertness."
- Dr Ankit Gupta

3. Types of food consumed

If you've noticed that you feel sleepier after a certain type of lunch, especially a heavy one, you're right. The type of food you eat for lunch can also impact how sleepy you are.

  • Meals that are high in carbohydrates like potatoes, bread, rice or pasta, and also simple sugars (like pizza, and pastries), can cause a rapid increase in blood sugar levels.

  • This hike in blood sugar levels can be followed by a crash in energy levels, leading to feelings of tiredness.
  • Additionally, large and heavy meals may require more energy for digestion, further contributing to post-meal drowsiness.

4. Hormonal changes

Eating can trigger the release of various hormones, including insulin and serotonin, which believe it or not, can influence your mood and your energy levels.

For example, the release of serotonin can promote feelings of relaxation and drowsiness. There are various food items that can promote serotonin, like:  

  • Eggs
  • Cheese
  • Pineapples
  • Tofu
  • Salmon
  • Nuts
  • Turkey

Also remember that if you're in a sleep deficit from insufficient sleep the night before, you are more likely to feel sleepy during the day, including after lunch.

Dr Ankit says, "Factors such as a warm or dimly lit environment, a comfortable chair or bed, or a quiet atmosphere can also make you feel more inclined to take a nap after lunch."

How can you avoid it?

There are days when we want to be productive and avoid that afternoon slump, and cannot afford to doze off. In such situations, there are certain things that you can do to mitigate post-lunch sleepiness: 

Dr Shyam Sharma, MBBS, a physician from Assam, says "When you consume an excessive amount of food, your digestive system expends 60-75 per cent of your body's energy to process it. As a result, your body redirects a significant portion of its energy from other functions to support the digestive system. This diversion of energy can induce feelings of drowsiness, as your body is spending considerable effort on breaking down food". He says that's why the best way to avoid sleepiness after lunch, is by avoiding overeating. 


There are other ways also, take a look: 

1. Eat a balanced meal that includes protein, complex carbohydrates, and healthy fats to provide sustained energy.

2. Stay hydrated throughout the day, as dehydration can contribute to feelings of fatigue.

3. Take short breaks to stand up, stretch, or walk around or even expose yourself to a little sunlight after eating to stimulate blood flow and alertness.

4. Also remember to have a good sleep cycle and ensure that you're well-rested in order to avoid feeling sleepy.

5. Finally, avoid large, heavy meals or excessive caffeine intake (as too much caffeine makes you tired and sleepy), especially in the afternoon. 

A 2022 study showed that our alertness follows a distinct pattern throughout the day, with two notable low points: the first occurs in the morning, typically between 2 and 7 am (when we are generally asleep), and the second takes place in the afternoon, generally from 2 to 5 pm.  


If possible, experts suggest that taking a nap can have several cognitive benefits and is an effective way to combat post-meal sleepiness after enjoying your lunch.

  • So, consider taking a short nap of 15 to 20 minutes right after finishing your meal (if possible). This can help your body relax and alleviate the drowsiness that often follows eating.
  • If not, take the steps that we have listed above that will help you fight that post-lunch sleepiness. 
Last updated: September 15, 2023 | 08:00
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