The idea that turkey makes us tired has been passed around holiday celebrations for a long time. But is it true? Turkey meat contains L-tryptophan, which is an essential amino acid that helps produce serotonin - the feel-good hormone. It also helps produce melatonin, which promotes sleep. But this doesn’t mean that it’s the turkey that's making you feel sleepy. In fact, you’d have to eat approximately 4 pounds of turkey by yourself, in one sitting for it to make you sleepy. The real reason we get drowsy after inhaling a big holiday feast is likely because we’ve consumed a lot of carbohydrates. Foods like stuffing, mashed potatoes, rolls, cornbread and desserts cause a rise in our blood sugar levels, followed by a crash. This crash is what leaves us feeling sleepy 60 to 90 minutes after eating.