Many people believe that eating turkey makes them sleepy, especially after Thanksgiving dinner. Turkey contains an amino acid called tryptophan, which can contribute to the production of serotonin and melatonin, two hormones that can affect mood and sleep. However, eating turkey alone is not enough to cause sleepiness. Rather, it is the combination of tryptophan and a large number of carbohydrates from other typical Thanksgiving foods, such as bread, potatoes, peas, corn, sugary drinks, and desserts, that can lead to sleepiness. Overeating in general, especially high-carbohydrate, high-fat meals, can also cause post-meal sleepiness. Additionally, the holiday season and the stress and excitement that come with it can also contribute to sleepiness. Therefore, while tryptophan in turkey may play a small role in causing sleepiness, it is not the only factor, and other lifestyle and dietary choices can also affect sleep quality.