Debunking the Myth: What is the feel good hormone in turkey?

October 18, 2025 •

4 min read

Despite popular belief, the drowsiness felt after a holiday meal is not primarily due to the tryptophan in turkey, but more so a result of overeating and the overall meal composition. While turkey does contain tryptophan, the amino acid precursor to the neurotransmitter serotonin, the idea that turkey alone contains the 'feel good hormone' is a long-standing nutritional myth.

Quick Summary

The long-standing myth that the tryptophan in turkey is solely responsible for post-meal sleepiness is debunked, explaining how serotonin synthesis from dietary tryptophan is more complex. A balanced diet, rather than a single food, is key for mood regulation and energy levels.

Key Points

The Tryptophan Myth: The idea that turkey is a special source of sleep-inducing tryptophan is a misconception, as its content is comparable to other meats.
Serotonin Synthesis Is Complex: Tryptophan must compete with other amino acids to enter the brain, making it difficult for the body to convert it into serotonin and melatonin from a protein-rich meal alone.
Overeating is the Culprit: Post-meal drowsiness is more likely caused by the sheer volume of food, especially high-carbohydrate dishes, which affect blood sugar and blood flow.
Diet and Mood Connection: A balanced diet rich in omega-3s, B vitamins, and antioxidants is crucial for mood regulation and brain health.
Other Tryptophan Sources: Many other foods, including cheese, soy, and seeds, are also rich in tryptophan.
Gut Health Matters: The gut-brain axis highlights the link between a healthy gut microbiome and improved mood, influenced by fiber and probiotics.

The idea that turkey is a special source of a 'feel good hormone' or sleepiness-inducing agent is a widespread myth, often associated with Thanksgiving feasts. The rumor suggests that the amino acid tryptophan, present in turkey, is converted into serotonin and then melatonin, leading to drowsiness. While the biochemical pathway connecting tryptophan to serotonin and melatonin is real, the effect from eating a typical portion of turkey is negligible and overshadowed by other physiological factors.

The Real Connection Between Tryptophan and Serotonin

Serotonin is a neurotransmitter that plays a crucial role in regulating mood, appetite, sleep, and overall well-being. The body synthesizes serotonin from the essential amino acid L-tryptophan, which must be obtained through diet. However, getting tryptophan from food into the brain to boost serotonin levels is a complex process. Tryptophan must compete with other amino acids, especially large neutral amino acids (LNAA), to cross the blood-brain barrier.

When you eat a high-protein meal like turkey, you consume many amino acids simultaneously. This glut of competing amino acids effectively prevents tryptophan from dominating entry into the brain. Therefore, the tryptophan in turkey does not get a privileged pass to ramp up serotonin production in a way that would cause noticeable mood or energy changes.

Why Your Big Meal Makes You Sleepy

If the tryptophan in turkey isn't the primary culprit for post-meal drowsiness, what is? The answer lies in the overall composition and quantity of the meal, rather than a single ingredient.

Carbohydrate Overload: A large holiday meal is typically rich in carbohydrates from foods like stuffing, mashed potatoes, and pie. High carbohydrate intake triggers the release of insulin. While insulin helps transport glucose into cells, it also helps remove other competing amino acids from the bloodstream, indirectly clearing a path for tryptophan to enter the brain more effectively. This effect, combined with the other factors below, can contribute to lethargy.
Overeating: Consuming a very large meal diverts significant blood flow to the digestive system, reducing it elsewhere, and can induce general fatigue.
Alcohol: Many holiday celebrations involve alcohol, a known sedative that compounds feelings of sleepiness.

Tryptophan in Turkey vs. Other Foods

Another reason the turkey myth is flawed is that turkey is not an exceptional source of tryptophan. Many other common foods contain comparable or even higher levels of this amino acid. A balanced diet provides sufficient tryptophan without relying on large quantities of a single food.

Here are some foods that contain tryptophan:

Soy products: Tofu and soybeans often contain very high levels of tryptophan.
Seeds: Pumpkin and sesame seeds are particularly rich sources.
Cheese: Parmesan and mozzarella have significant amounts of tryptophan.
Other Meats: Chicken, pork, and beef contain similar levels of tryptophan to turkey.
Fish: Tuna and salmon are excellent sources of both tryptophan and omega-3 fatty acids.
Nuts: Cashews and almonds provide tryptophan along with other healthy fats.

Turkey vs. Chicken Nutrition Comparison

To put the nutritional content of turkey into perspective, let's compare it to another popular poultry, chicken. Both offer high-quality protein, but there are some differences.


Nutrient (per 100g cooked, skinless breast)	Turkey	Chicken
Calories	~189	~197
Protein	~28.5g	~27.3g
Fat	~7.39g	~13.6g
Tryptophan	~214mg (3 oz.)	~237mg (3 oz.)

Note: The exact tryptophan content can vary slightly depending on the data source and preparation.

The Wider Role of Nutrition in Mood

While the focus on tryptophan in turkey is misplaced, nutrition undeniably plays a vital role in mental health. The gut-brain axis is a two-way communication system linking the digestive system and the central nervous system, where nutrients, gut bacteria, and neurotransmitters all interact. A healthy diet supports a diverse gut microbiome, which is associated with improved mood and reduced anxiety.

Several key nutrients, not just tryptophan, are critical for optimal brain function and mood regulation:

Omega-3 Fatty Acids: Found in fatty fish, walnuts, and flaxseeds, these fats are essential for brain health and can help reduce symptoms of depression.
B Vitamins: Found in leafy greens, whole grains, and legumes, B vitamins are crucial for energy production and neurotransmitter synthesis.
Antioxidants: Fruits and vegetables are rich in antioxidants that protect the brain from inflammation and oxidative stress, which can negatively affect mental health.
Water: Even mild dehydration can impair mood and concentration.
Regular Meals: Eating at regular intervals prevents blood sugar drops that can cause mood swings and irritability.

Conclusion

So, what is the feel good hormone in turkey? The short answer is that the concept is a myth based on a misinterpretation of biochemistry. The amino acid tryptophan is a precursor to serotonin, but the amount in turkey is not exceptional, and its uptake into the brain is limited by competition with other amino acids. A balanced approach to nutrition, focusing on a variety of whole foods, is far more impactful for regulating mood and energy than singling out any one ingredient. By focusing on nutrient-rich meals, staying hydrated, and managing overall intake, you can effectively support your mental well-being and leave the post-meal food coma to overeating, not the bird. You can find more comprehensive nutritional information on reputable sources like Nutrition.gov.

Frequently Asked Questions

No, this is a myth. The 'feel good hormone' is serotonin, which the body synthesizes from the amino acid tryptophan. While turkey contains tryptophan, so do many other foods, and it's not present in a high enough concentration to significantly impact mood or cause sleepiness on its own.

The sleepiness after a large meal, like a holiday feast, is more likely caused by overeating and a high intake of carbohydrates and fats, not the turkey. Consuming a large volume of food diverts blood to the digestive system, leading to fatigue. Alcohol can also contribute to drowsiness.

The body uses tryptophan as a precursor to synthesize serotonin in a two-step enzymatic process. However, to reach the brain, tryptophan must compete with other amino acids, which is difficult after consuming a protein-rich meal with multiple amino acids, like turkey.

Many foods contain tryptophan, some in higher amounts than turkey. Examples include cheese (like Parmesan and mozzarella), soy products (tofu, soybeans), seeds (pumpkin, sesame), and other meats and fish.

Yes, a strong connection exists through the gut-brain axis, which links digestive health and mental well-being. A balanced diet providing essential nutrients, like omega-3s, B vitamins, and antioxidants, is crucial for optimal brain function and stable mood.

When you eat carbohydrates, your body releases insulin, which helps remove some competing amino acids from the bloodstream. This can indirectly increase the amount of tryptophan that can cross the blood-brain barrier, but this effect is often minor compared to the impact of overeating.

Focus on a balanced diet rich in fruits, vegetables, whole grains, and lean proteins. Include omega-3 fatty acids from fish or walnuts, ensure adequate B vitamin intake, and focus on overall gut health. Eating regular meals can also help stabilize blood sugar and mood.