Sometimes people blame that after-dinner drowsiness on the turkey. Turkey meat contains an amino acid called L-tryptophan, and this compound helps makes you sleepy. But you'd have to eat turkey on an empty stomach with nothing else to really make you snooze. Thanksgiving foods have a lot of carbohydrates -- those are nutrients found in things like bread, potatoes, and pumpkin pie. These foods can help make you sleepy. And you probably eat a bigger meal than normal at Thanksgiving. That makes your stomach work harder to digest the food, and more blood flows to your stomach and away from your brain. All together, a traditional Thanksgiving dinner is designed to make you sleepy!