What is it Called When You are Tired After Eating Too Much? (Postprandial Somnolence)

January 4, 2026 •

3 min read

According to the Sleep Foundation, nearly every person has experienced the phenomenon of feeling sleepy after eating a meal. This common occurrence, colloquially known as a 'food coma,' has a proper medical name: postprandial somnolence.

Quick Summary

The feeling of tiredness after eating a large meal is medically known as postprandial somnolence. This fatigue is primarily caused by hormonal shifts triggered by meal composition, size, and the body's natural circadian rhythm.

Key Points

Postprandial Somnolence: The medical term for the tiredness felt after eating too much, also known as a 'food coma'.
Hormonal Shifts: Insulin spikes from high-carb meals lead to the production of serotonin and melatonin, contributing to post-meal drowsiness.
Meal Composition Matters: Large meals, especially those high in carbohydrates and fats, are more likely to induce postprandial somnolence.
The Circadian Rhythm Connection: The body's natural afternoon energy dip enhances post-lunch food coma effects.
Prevention Strategies: To minimize tiredness, eat smaller, balanced meals, stay hydrated, exercise lightly after eating, and ensure adequate sleep.
Medical Implications: While generally harmless, persistent or severe post-meal fatigue can sometimes indicate an underlying condition like insulin resistance or diabetes.

Understanding Postprandial Somnolence

Postprandial somnolence is the scientific term for the drowsiness experienced after a meal. Several factors contribute to this 'food coma,' including the energy your body expends on digestion, especially after large, calorie-dense meals. The types of food consumed also play a role, with high-carbohydrate and high-fat meals being more likely to induce sleepiness.

The Hormonal and Neurological Response

Hormonal changes are a key factor in post-meal fatigue. Consuming carbohydrates leads to insulin release to manage blood sugar. This process allows more tryptophan to reach the brain, where it's converted into serotonin and melatonin, both of which promote sleepiness. Additionally, the body's 'rest and digest' system is activated after eating, contributing to low energy. The hormone orexin, which promotes alertness, is also inhibited after a meal.

The Role of Meal Composition and Timing

Meal composition significantly impacts postprandial somnolence. Large meals require more digestive effort, diverting resources to the gut. This is why the effect is often noticed after large feasts. The body's natural circadian rhythm also contributes; the afternoon dip in alertness can make post-lunch tiredness more pronounced. Factors like poor sleep, stress, and alcohol can worsen these effects.

How to Minimize Post-Meal Tiredness

Eat Smaller, More Frequent Meals: Avoid overwhelming your digestive system.
Prioritize Balanced Meals: Combine protein, fiber, and healthy fats with complex carbohydrates for stable blood sugar.
Stay Active: A short walk post-meal can help digestion and increase alertness.
Optimize Sleep: Adequate sleep reduces daytime energy dips.
Limit Alcohol: Alcohol can increase drowsiness.
Stay Hydrated: Dehydration contributes to fatigue.
Manage Stress: Stress impacts digestion and energy levels.

Comparison: Postprandial Somnolence vs. Other Fatigue

It is helpful to differentiate postprandial somnolence from other types of tiredness:


Feature	Postprandial Somnolence	General Fatigue	Reactive Hypoglycemia
Timing	Within 30 minutes to 2 hours of eating.	Can occur anytime due to various factors.	2–5 hours after a meal, often more severe.
Cause	Hormonal shifts, digestion, circadian rhythm.	Lifestyle, medical conditions.	Insulin overproduction and low blood sugar.
Symptoms	Drowsiness, lethargy.	Persistent tiredness, exhaustion.	Shakiness, sweating, confusion.
Associated Factors	Large, high-carb/fat meals.	Poor sleep, stress, depression.	Prediabetes, diabetes.

Conclusion

Feeling tired after eating, or postprandial somnolence, is a common biological process involving hormonal changes and the body's natural rhythm. While usually temporary, persistent or severe fatigue might signal underlying health issues like insulin resistance. Practicing mindful eating, consuming balanced meals in moderation, and maintaining a healthy lifestyle with sufficient sleep and exercise can help reduce this 'food coma' effect. Consult a doctor if symptoms are severe or ongoing.

For more detailed information, the Cleveland Clinic offers insights into the causes and management of post-meal tiredness.

Is it a food coma or postprandial somnolence?

The terms are interchangeable: "Food coma" is the common term, while "postprandial somnolence" is the medical term for post-meal sleepiness.

What foods are most likely to cause a food coma?

High-carb and high-fat meals: These types of meals are linked to postprandial somnolence due to insulin spikes and increased digestive effort.

Is the turkey on Thanksgiving really to blame?

No, it's a common myth: The large amount of carbohydrates, fats, and calories in a holiday meal are the main cause, not just the tryptophan in turkey.

How can I prevent the afternoon slump after lunch?

Balance and moderation are key: Eat a balanced meal with protein, fiber, and complex carbs and avoid large portions. A short walk afterwards can also help.

When should I be concerned about feeling sleepy after meals?

If symptoms are persistent or severe: Regular, extreme fatigue with symptoms like dizziness or sweating could indicate an underlying issue like diabetes and should be discussed with a doctor.

Does getting enough sleep prevent a food coma?

Yes, quality sleep helps: Lack of sleep can worsen the natural afternoon energy dip, making postprandial somnolence more noticeable. Sufficient rest can lessen this effect.

Does it help to drink coffee after eating to combat tiredness?

Use caffeine cautiously: A little caffeine might help, but too much can negatively impact your sleep cycle and potentially increase fatigue later.

Frequently Asked Questions

The medical term for feeling tired after eating too much is postprandial somnolence.

Sleepiness after a large meal is caused by a complex mix of hormonal changes, especially related to insulin and serotonin, combined with the body's focus on digesting a large volume of food.

The idea that turkey alone makes you sleepy is a myth. While it contains tryptophan, the overall high-calorie, high-carb, and high-fat content of a typical holiday meal is the real cause of the fatigue.

You can prevent a food coma by eating smaller, more frequent meals, choosing balanced meals with lean protein and fiber, staying hydrated, and engaging in light physical activity after eating.

For most people, postprandial somnolence is a normal and harmless response. However, if it is severe, frequent, and accompanied by other symptoms like dizziness or confusion, it may be a sign of poor blood sugar control or diabetes, and you should see a doctor.

High-carb meals cause a spike in blood sugar, leading to a release of insulin. This process increases the relative amount of tryptophan available to the brain, which is converted into sleep-inducing serotonin and melatonin.

The fastest way to alleviate a food coma is to get up and move. A short walk can help regulate blood sugar and increase alertness. Staying hydrated and getting some fresh air can also be beneficial.