Why Do I Feel Sleepy After Eating Lunch?

How and Why Do I Feel Sleepy after Eating Lunch?

Drowsiness, fatigue and lethargy are commonly experienced after meals. Let’s have a comprehensive answer to “Why do I feel sleepy after eating lunch?” Mostly, these feelings are induced after the intake of a heavy and rich meal.

However, a small snack may also lead to feeling groggy. This is because of the process of digestion. Also the intake of certain nutrients causes one to feel sleepy after eating. The following discussion answers to your question, “Why do I feel sleepy after eating lunch?”

Why Do I Feel Sleepy After Eating Lunch?

Digestion and Blood Flow

As you learn about the process of digestion, you will get answer to “Why do I feel sleepy after eating lunch?” Digestion starts after the intake of meal. It diverts the flow of blood to the digestive system. The food particles are broken down into small nutrients. These are absorbed into the blood stream. The blood flow is diverted away also from the brain. It leads to a feeling of drowsiness. You may also experience lethargy. However, one should not succumb to this feeling. Falling asleep right after a meal can lead to certain digestive problems, such as reflux. Taking a light walk after eating may help in shaking off lethargy. It improves blood flow and aids in proper digestion. Given below are some other reasons regarding “Why do I feel sleepy after eating lunch?”

Intake of Simple Sugars

Simple sugars are a class of nutrients. They lead to an immediate rise in the blood sugar level. As a result, the pancreas is stimulated to release insulin. Insulin is a hormone which converts sugar into fat for the purpose of storage. In simple words, a rise in blood sugar leads to insulin production. This is done to restore the level of sugar in the blood.

The conversion of this sugar into fat leads to a decline in energy levels. So, it is the reason “Why do I feel sleepy after eating lunch?” An individual inevitably feels drowsy after the intake of meals or snacks containing simple sugars. These include white bread, white rice, artificial juices, carbonated drinks, mashed potatoes, doughnuts, cakes, cookies, ice cream and other sweet snacks.

Serotonin and Melatonin Production

Do you know the relevance of serotonin to your question, “Why do I feel sleepy after eating lunch?” Serotonin is a neurotransmitter which leads to mood swings, depression and drowsiness. Similarly, melatonin is a chemical that induces sleep.

The production of both of these substances starts after the intake of a meal high in simple carbohydrates. The body should store the carbohydrates and restore the blood sugar level. Insulin is secreted by the pancreas. It causes an increase in levels of serotonin and melatonin in the brain through a chain reaction.

Therefore, after having a fast food meal or carbohydrate-rich snacks, an individual is feels sleepy and lethargic. Read on to find out more information related to your question, “Why do I feel sleepy after eating lunch?”

High Intake of Fat

Fatty meals including fried food and oily snacks also lead to sleepiness. The intake of fat affects the brain by influencing responses of the nervous system. Therefore, drowsiness starts after eating foods like potato chips, grilled cheese, beef cheese burger or corn chips. So, there is no need to be concerned “Why do I feel sleepy after eating lunch?” The fats are guilty here.

Age and Physical Fitness

It has been proved through the above discussion that the wrong diet can cause lethargy. Also you feel sleepy after eating. Other factors to provide answer to “Why do I feel sleepy after eating lunch?” include age and poor physical fitness. Young individuals mostly have a higher metabolic rate. With age the metabolic rate decreases through a continuation of poor eating habits and lack of physical exercise. On the other hand, those who are physically fit are mostly able to stay fresh after meals.

Poor Sleeping Habits

Those who burn the midnight oil are more easily overwhelmed by drowsiness after meals as compared to those whose sleeping patterns are regular. Poor sleeping habits are also relevant to the question “Why do I feel sleepy after eating lunch?” Staying up late night and getting insufficient time to rest leads the body and the brain to feel exhausted. As a result, more lethargy is followed after meals. There is a strong urge to take a nap after the intake of lunch or a midday snack.


Overeating is also one of the main reasons regarding “Why do I feel sleepy after eating lunch?” Eating too much causes you to overindulge in the wrong kinds of foods. They may be high in sugar and fats. These substances in turn lead to the production of brain chemicals. These chemicals are responsible for drowsiness. On the other hand, a heavy meal also affects the flow of blood. It is diverted away from the brain to the digestive system as discussed above.

Lack of Important Nutrients

A meal which lacks important nutrients required for an active and alert brain inevitably leads to lethargy. One of such nutrients is the mineral zinc. Vitamin B complex also helps individuals in boosting their brain power and fighting everyday lethargy. Similarly, the mineral iron also improves one’s vigor and energy levels by improving blood circulation throughout the body.

On the other hand, it is also necessary to include plenty of fiber in one’s diet for proper digestion. In addition, fiber also makes one feel full and prevents overeating. It means the use of fiber can lessen your concerns regarding “Why do I feel sleepy after eating lunch?”


The intake of sufficient water is important for the body in a number of different ways. It is required for various metabolic reactions. Water aids digestion and keeps the brain active. On the other hand, dehydration causes an individual to feel dull. Therefore, drowsiness is experienced commonly after meals. You should consume sufficient water during the day. Otherwise, the thought of “Why do I feel sleepy after eating lunch?” will pop up in your mind.

Feeling sleepy after meals is a common scenario. Majority of individuals do not pay any special attention to it. However, it indicates underlying health issues and poor dietary habits. Therefore, you must improve your health condition. Turn to physical fitness programs and consume a better diet. You will stay fresh and alert even after eating.

About the Author

Posted by: M. Isaac / Senior writer

A graduate in biological sciences and a PhD scholar (NCBA&E University, Lahore), M. Isaac combines his vast experience with a keen and critical eye to create practical and inherently engaging content on the human body. His background as a researcher and instructor at a secondary school enables him to best understand the needs of the beginner level learners and the amateur readers and educate them about how their body works, and how they can adopt a healthier lifestyle.

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