The Real Reason: Why Do We Feel Sleepy After Eating Lunch?

Sushmita Sengupta  |  Updated: April 24, 2017 16:12 IST

The Real Reason: Why Do We Feel Sleepy After Eating Lunch?
  • After a heavy meal, our insulin levels spike which causes the drowsiness
  • High carb lunch also induces sleep
  • Body's focus after a meal is towards digestion, which takes energy
Imagine this. You are at work, all charged up and have slotted the 3 4 P.M. window for an important assignment. You have your lunch around 2 P.M, and thereafter find yourself struggling to keep your eyes open! You are lazy and lethargic, suddenly. What could be the reason of the post lunch slump? Is there a reason why you feel this way? Certainly. 

The phenomena is common with everybody who has a slightly heavier lunch or one that is rich in carbohydrates. Sneaking an afternoon siesta is actually a very common practice in India. In parts of Bengal shop owners shut their shops from 3 P.M. to 5 P.M. to catch up on their afternoon nap or ‘Bhaater Ghoom’ as they call it, after a meal packed with carb-rich rice, fish,dal and vegetables. 

Here's the real reason why we feel sleeping after having lunch. After a heavy meal, our insulin levels spike. This is because, for everything that we eat, our pancreas produces insulin to regulate our blood sugar levels. The heavier the meal, the greater will be the production of insulin. With the increased secretion of insulin, our body produces the sleep hormone which where it gets metabolized into serotonin and melatonin in our brain and they induce drowsiness. This nervous response tells our body to slow down, stop doing what we're doing and let our body and mind focus on digestion.
(Also read: 9 Reasons Why You Need to Relax and Get Good Sleep)
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Bangalore-based nutritionist Dr. Anju Sood explains the physiology behind this, "There are a couple of factors working here. The most important function after eating is digestion which requires energy. So, all your blood streams get diverted towards the task of digestion, hence you feel the energy deficit and also drowsy. Other than that it also depends on the food that you are eating. If your meal is loaded with fat, it will take more time to digest. If you have a carb-rich meal, the sugar goes to the liver and an increased amount of insulin is generated. In this process, the neurotransmitter serotonin also gets stimulated which induces sleep.”

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Dr. Sood adds, “The process is the same after dinner too. It’s just because we do go to sleep eventually at night, we don’t realize while in the afternoon we still have the rest of the day. Hence, the ‘feeling of sleepiness’ is more evident."

(Also read:10 Common Mistakes That Could Be Ruining Your Sleep)

What can you do to avoid feeling sleepy?

CommentsNothing much as the condition is absolutely normal. However, you can cut down the slump, and stay alert by checking your diet. The more you eat, the more energy it takes to break down the food, and the more sleepy you feel. So keep your lunch light and consume smaller meals throughout the day. Smaller meals at regular intervals would keep you fuller and prevent you from binging on high-carb or salty foods. Avoid too many carbs or fats for lunch and eat foods that are easily digestible. Diabetic patients may have to take extra care. 

About Sushmita SenguptaSharing a strong penchant for food, Sushmita loves all things good, cheesy and greasy. Her other favourite pastime activities other than discussing food includes, reading, watching movies and binge-watching TV shows.

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