What Makes You Sleepy After Eating?

Feeling sleepy after eating, or postprandial somnolence, is common. Also known as the post-lunch dip or food coma, research shows several factors are at play.

What, when, and how much you eat, as well as a natural dip in circadian rhythms (your body’s internal clock) can lead to post-meal fatigue. While it happens to most people on occasion, It can also signal a hidden a health issue.

This article discusses sleepiness after eating. It explains some theories about why you may feel sleepy after meals, medical conditions linked to post-meal tiredness. It also offers tips for staying alert after eating.

What Is Post-Prandial Somnolence?

Post-prandial somnolence simply means feeling sleepy after eating. When it happens after lunch, it’s called the post-lunch dip or 3 p.m. slump. After a big holiday meal, its often referred to as a food coma.

Tiredness after eating a normal phenomenon that most people encounter from time to time. However, if the fatigue interferes with your daily life and responsibilities, talk to your healthcare provider. It could be a sign of an underlying medical condition.

What Causes Post-Meal Fatigue?

Researchers have identified various factors that may contribute to wanting to sleep after eating. These include:

• What you eat: Meals that are high in either carbohydrates or fat are more likely to make you tired than meals high in protein.
• How much you eat: Eating a lot of calories in one sitting is also linked to post-meal fatigue.
• When you eat: The timing of meals can impact energy levels.
• Specific nutrients: Research shows tryptophan, melatonin, and other phytonutrients promote sleepiness.
  

What Foods Can Make You Tired?

Nutrients in certain foods can make you feel tired after eating. Eating them before bed can help you get a good night’s sleep. However, if you have them for lunch, you might find yourself wanting to nap under your desk.

Here is a look at some fatigue-inducing nutrients and the foods they are found in.

Melatonin

Melatonin is a hormone the brain produces in response to darkness. It prompts the mind and body to start winding down for the day and makes you sleepy. Melatonin is also found in many foods and may contribute to post-meal energy slumps.

Foods with a high melatonin content include:

• Barley
• Corn
• Cranberries
• Cucumbers
• Eggs
• Mushrooms
• Oats
• Pistachios
• Rice
• Salmon
• Strawberries
• Tart cherries
• Wheat
  

Tryptophan

Tryptophan is an amino acid that might make you feel a little sleepy. The body converts tryptophan to serotonin and then to melatonin, which as noted above, can make you tired.

Foods that are high in tryptophan include:

• Chicken
• Egg whites
• Fish
• Milk
• Sunflower seeds
• Peanuts
• Pumpkin seeds
• Sesame seeds
• Soy beans
• Turkey

Carbohydrates

Research shows carbohydrate-heavy meals can make you tired. In particular, foods with a high glycemic index (GI)—a measure of how specific carbohydrates raise blood sugar—are more likely to cause post-meal fatigue.

Experts suspect fluctuating blood sugar levels are to blame. Your body converts carbohydrates to sugar. High glycemic-index foods can cause your blood sugar to rise quickly and then crash. This drop in sugar levels can also make you sleepy after eating.

Foods with a high glycemic index include:

• Baked goods, such as white or wheat bread
• Cereals, like cornflakes and instant oatmeal
• Potatoes
  
• Sugar (sucrose)
• Watermelon
• White rice

Fats

High fat consumption is linked to increased daytime fatigue. But studies suggest the type of fat makes a big different. In particular, saturated fats and trans fats have been shown to increase post-meal fatigue.

Foods high in unhealthy fats include:

• Baked goods
• Beef
• Butter
• Cheese
• Cream
• Dark meat poultry, especially with skin
• Deep-fried foods
• Ice cream
• Lamb
• Lard
• Palm oil and palm kernel oil
• Pork
• Whole-fat dairy products
  

Body Rhythms

Post-lunch sleepiness often has more to do with the natural timing of an increased tendency towards sleep than the food you consume. Two phenomena contribute to this. They include:

• Sleep drive: The sleep drive is due to the gradual build-up of a chemical within the brain called adenosine. This chemical reaches its peak right before bedtime, but it is also higher in the afternoon compared to the morning. Thus, the longer a person stays awake, the more adenosine accumulates, increasing the desire for sleep.
• Circadian rhythm: The second process that contributes indirectly to sleepiness is the circadian rhythm. The circadian rhythm functions like a clock that controls periods of wakefulness and sleep. It increases throughout the day to keep you awake and counteract the increasing levels of adenosine.

There is a dip in this pattern in the early afternoon. This lull typically occurs seven to nine hours after waking up. When the alerting signal dips, the underlying sleepiness shows itself, and you feel sleepy.

Interestingly, night owls (who may naturally fall asleep and wake later) often experience a delay in the timing of this afternoon lull as well. As a result, they may not feel sleepy until several hours later.

Other Causes

Underlying health conditions

Diabetes

Hypoglycemia

Anemia

Thyroid Problems

Low Blood pressure (postprandial hypotension )

Medications 

Mild dehydration

Alcohol: Drinking alcohol may cause drowsiness. It does this because it enhances the effects of adenosine. However, in most cases, this is not what contributes to feeling sleepy after lunch.

Easing Post-Meal Drowsiness

While you may not be able to avoid it entirely, there are some things you can try to counteract the sleepiness that occurs after meals:

• Eat well-balanced meals. Avoiding meals heavy in carbohydrates or proteins can help you avoid increases in blood sugar (and subsequent crashes) and maintain adenosine levels.
• Get more nighttime sleep. If you experience sleep deprivation, this after-lunch sleepiness can be more pronounced. In addition, sleep disorders such as obstructive sleep apnea may make this worse.
• Expose yourself to enough daylight. Circadian rhythms are impacted by sunlight. Our bodies are more alert when exposed to light, and less alert when it’s dark. Research shows exposure to bright light after lunch help to counteract the afternoon slump.
• Get regular exercise. The impact of exercise on sleep is well known. However, be sure to pay attention to when you exercise. For some, exercising too close to bedtime can make it harder to fall asleep.
• Nap for 10 to 20 minutes. Sometimes, a post-meal nap is an option. But keep it short; anything longer than 20 minutes or so could impact your ability to sleep at your normal time.
  

A Word From Verywell

Feeling tired after eating is a common physiological response and generally not a cause for concern. To mitigate the occurrence of food comas, one can adopt simple yet effective measures, including moderating portion sizes, opting for more balanced meals, limiting alcohol consumption, staying adequately hydrated, ensuring sufficient overall sleep, exposing oneself to bright lights, or even indulging in a short nap.

— SMITA PATEL, DO, MEDICAL EXPERT BOARD