Is there something in turkey that makes you sleepy?

It's Thanksgiving Day, and your waistband is groaning. You're heavy-lidded as you lift one more forkful of pumpkin pie to your mouth. Is a natural sedative called tryptophan really the reason you want a nap after Thanksgiving dinner?

Turkey does have the makings of a natural sedative in i­t, an amino acid called tryptophan. Tryptophan is an essential amino acid, meaning that the body can't… » Full Story on HowStuffWorks