This notion stems from tryptophan, one of the essential amino acids that acts as a building block for protein. When consumed, tryptophan converts into niacin that plays important roles in regards to energy production and tryptophan, a chemical in the brain associated with relaxation and sleep. Chowing down on the Thanksgiving, tryptophan-containing turkey has been assumed to lead to tiredness and an afternoon nap. Although an educated assumption, turkey contains no more (if not less) tryptophan than other poultry products such as chicken. In reality, turkey PLUS all of the stuffing, mashed potatoes, and pies lead to sleepiness. When large meals are consumed, the body goes into "rest and digest" mode. The gut is given the most attention during this time, as it takes a high amount of energy to digest that holiday meal and second or third helpings. Other organs, like the brain, slow down and move into a resting state, resulting in the want or need for a nap. The oft-repeated turkey myth stems from the fact that turkey contains the amino acid tryptophan, which forms the basis of brain chemicals that make people tired. But turkey isn't any more sleep-inducing than other foods. In fact, consuming large amounts of carbohydrates and alcohol may be the real cause of a post-Thanksgiving-meal snooze, experts say.