How much turkey do you have to eat to be sleepy? Debunking the Tryptophan Myth

October 23, 2025 •

4 min read

According to nutrition experts, you would have to consume about 8 pounds of turkey in one sitting to get a supplemental dose of tryptophan large enough to induce sleepiness. The popular belief that a few slices of turkey can make you tired is a widespread misconception, as the true cause of post-feast drowsiness is far more complex than a single amino acid.

Quick Summary

This article explores the science behind the 'food coma,' clarifying that overeating, high-fat and carbohydrate-heavy meals, and alcohol consumption are the true culprits behind post-dinner drowsiness, not the tryptophan in turkey. It compares the tryptophan content of turkey to other foods and explains the body's digestive processes.

Key Points

Turkey's Tryptophan is Not Exceptional: Many other common foods like chicken, cheese, and seeds contain similar or higher concentrations of tryptophan.
Overeating is the Primary Cause: Consuming a large volume of food, regardless of its type, redirects blood flow to the digestive system, causing sluggishness.
Carbohydrates Are Key: A heavy meal rich in carbohydrates causes a blood sugar spike and crash, leading to feelings of fatigue.
Competition Limits Tryptophan Absorption: When eaten with other proteins, tryptophan competes with other amino acids to enter the brain, minimizing its effect.
Alcohol and Timing Play a Role: Alcohol is a depressant, and large meals often coincide with the body's natural afternoon energy dip, contributing to sleepiness.
A Balanced Diet Promotes Stable Energy: Eating meals with a mix of protein, complex carbs, and healthy fats helps avoid blood sugar crashes and post-meal fatigue.

The Tryptophan Truth: A Turkey Tale of Misconception

For decades, the idea that the tryptophan in turkey causes post-dinner drowsiness has been a popular and widely accepted piece of folklore. The story goes that tryptophan, an essential amino acid, helps produce serotonin and melatonin, neurotransmitters and hormones that regulate sleep and mood. However, this simple narrative overlooks the complex reality of human digestion and biochemistry. While turkey does contain tryptophan, it is in no way a magic sedative or a uniquely concentrated source. In reality, a typical serving of turkey contains only a modest amount of tryptophan, comparable to or even less than other common protein sources like chicken, beef, or cheese.

For tryptophan to have a noticeable effect on the brain, it needs to cross the blood-brain barrier. When you eat turkey as part of a large, protein-rich meal, the tryptophan must compete with a host of other amino acids for entry into the brain. This competition significantly limits the amount of tryptophan that can get through, effectively muting any potential sleep-inducing effects. The 'food coma' is not a single-ingredient issue but a multifactorial consequence of eating habits and meal composition.

The Real Culprits Behind Your Post-Meal Nap

So, if it’s not the turkey, what is making you feel so sleepy after a large meal? The answer lies in a combination of factors related to how your body processes and digests a heavy, calorie-dense feast. The typical holiday meal is rich in more than just tryptophan; it’s loaded with carbohydrates and fats, which play a much larger role in inducing a sluggish feeling.

The Role of Carbohydrates

Eating a significant amount of carbohydrates—found in side dishes like mashed potatoes, stuffing, and desserts—causes a spike in your blood sugar. This triggers the release of insulin, which helps shuttle glucose from the bloodstream into your cells. This process also helps clear other competing amino acids from the bloodstream, allowing a proportionally higher amount of tryptophan to potentially enter the brain. The subsequent drop in blood sugar after the initial spike can lead to a feeling of fatigue and a lack of energy. While this mechanism does involve tryptophan, it's the large quantity of carbs, not the turkey alone, that creates the right conditions for this effect.

The Digestive Strain of Overeating

Consuming a large volume of food, regardless of its composition, requires your body to work overtime to digest it. This process diverts blood flow to your digestive system and away from other parts of the body, including the brain. The redirection of energy and resources can cause a feeling of lethargy and decreased alertness, what many people describe as a food coma. The sheer physical effort of breaking down a large meal is a significant contributor to postprandial somnolence.

Alcohol and Circadian Rhythms

Alcohol is a depressant that can cause drowsiness and make you feel more sleepy, especially when consumed alongside a heavy meal. Additionally, your body has natural energy dips throughout the day, and for many people, a slump occurs in the afternoon. A large, heavy lunch perfectly aligns with this natural drop in energy, making it much easier to nod off. Finally, the holiday season can be a time of stress and altered sleep schedules, meaning you might already be tired before you even sit down to eat.

Tryptophan Comparison: Turkey vs. Other Foods

To illustrate that turkey is not an unusually high source of tryptophan, here is a comparison of the tryptophan content per 100 grams of several common foods.


Protein Source	Tryptophan Content (mg/100g)	Notes
Roasted Chicken Breast	~249	Often has slightly more tryptophan per gram than turkey.
Roasted Turkey Breast	~252	High, but not exceptionally higher than other poultry.
Ground Pork Chop	~250	Comparable to turkey and chicken breast.
Parmesan Cheese	~560	Significantly higher than turkey.
Yellowfin Tuna	~326	Another high source of tryptophan.
Pumpkin Seeds	~163	A notable plant-based source.
Tofu (firm)	~593	A very high plant-based source.
Eggs (whole)	~170	Contains a healthy amount of the amino acid.

A Balanced Diet for Optimal Sleep

While a large meal is the most likely cause of sleepiness, a balanced approach to eating can help regulate your sleep patterns. Opting for meals that include a mix of lean protein, complex carbohydrates, and healthy fats can help keep blood sugar levels stable, preventing the energy crash that can lead to drowsiness. Incorporating foods rich in magnesium (like spinach and nuts) and natural melatonin (like tart cherries and eggs) may also support better sleep. Avoiding excessive amounts of simple sugars and high-fat foods, especially before bedtime, is a key strategy for maintaining steady energy and promoting restful sleep. For more information on the intricate links between nutrition and sleep, consulting a reputable resource like the Sleep Foundation can be helpful.

Conclusion: The Final Verdict on Post-Turkey Sleepiness

The notion that you have to eat an ungodly amount of turkey to become sleepy is a powerful and persistent myth. While turkey contains tryptophan, so do many other foods, and the amount present in a typical serving is not potent enough to function as a sedative. The true causes of post-meal fatigue are almost always related to overindulging in large, calorie-dense meals that are high in carbohydrates and fats. These foods trigger a complex digestive process and insulin response that results in a temporary energy lull. By understanding the real science behind the 'food coma,' you can adjust your eating habits to better manage your energy levels and avoid the post-feast snooze.

Visit the Sleep Foundation for more information on the diet-sleep connection

Frequently Asked Questions

The myth suggests that the amino acid tryptophan, found in turkey, is responsible for post-meal sleepiness. In reality, the amount of tryptophan in turkey is not exceptional, and its effect is overshadowed by other factors like overeating and high-carb consumption.

To get a large enough dose of tryptophan from turkey to feel its sedative effects, you would need to eat an extremely large amount, potentially 8 pounds or more, which is not realistically achievable in a single meal.

The main causes of a 'food coma' are overeating, consuming a large number of carbohydrates that cause a blood sugar spike and crash, and the redirection of blood flow to the digestive system.

Yes. Foods like Parmesan cheese, tofu, and other meats and fish can have a similar or higher concentration of tryptophan per gram compared to turkey.

Yes, but not in the way the myth suggests. Carbohydrates can aid in the absorption of tryptophan into the brain, but the resulting fatigue is more a product of the blood sugar spike and crash caused by high-carb consumption rather than the tryptophan itself.

Other factors include drinking alcohol, which is a depressant, and your body's natural circadian rhythm, which causes an energy dip in the afternoon. Pre-existing sleep deprivation from late nights can also make you more susceptible.

To avoid feeling tired, try eating smaller, more balanced meals with lean protein and complex carbohydrates. Staying hydrated, limiting alcohol, and going for a light walk after eating can also help.