Despite popular belief, it’s not the tryptophan in the turkey causing that postprandial drowsiness—in fact, turkey has about the same amount of tryptophan as other poultry. It’s just the sheer amount of food. As the amount of blood going to the digestive system is increased to handle all that turkey and pie, less blood is available to go to the brain. About the only mental challenge we can handle after that enormous meal is sitting on the couch watching football.
