No, turkey is not what causes you to be sleepy, yes tryptophan is in turkey and yes tryptophan is an amino acid that is used to make the protein serotonin which the body uses to make melatonin which is associated with drowsiness and sleep but there is not enough tryptophan in turkey to make you sleepy, not only does it have to compete with other proteins in the body but chicken has more typtophan in it than turkey does, so the minuscule amount of it in your body doesn't affect you much. It is actually due to the large amounts of carbohydrates you ingest
