Why is it you feel so sleepy after Thanksgiving dinner?  Is the turkey really the guilty party?  Who is the true culprit of the lethargic feeling experienced after a heavy Thanksgiving dinner?  Is it just an act to get out of dish duty?

Lets start with the facts:  We know Turkey contains L-tryptophan, an essential amino acid with a documented sleep inducing effect- a natural sedative.  The body cannot produce tryptophan; we have to get tryptophan and other amino acids from food.  Tryptophan helps the body produce niacin, which assists in the production of serotonin, a chemical that acts as a calming agent in the brain.  So it sounds like the turkey is the guilty party after all, however, it is not.  L-Tryptophan only has those effects if it is taken on an empty stomach, without other amino acids or protein.

So why is it we feel so sleepy after a heavy thanksgiving dinner if it’s not the turkey?  I suppose the word “heavy” may be the key here.  Thanksgiving dinner is heavy and high in carbohydrates, as well as fats.  Carbohydrates fuel the pancreas to emit insulin, which causes amino acids to battle tryptophan and causes it to leave the bloodstream and enter muscle cells, which in turn amplifies the concentration of tryptophan in the bloodstream. Serotonin is synthesized and you begin to feel sleepy.  Fats take a significant amount of energy to digest, which also results in fatigue.  If you throw alcohol into the mix you are going to intensify the feeling even more.