Let's review the common concept for a moment: people think the tryptophan in turkey makes people tired, especially on Thanksgiving (when so much is eaten). Is this true? Or a myth?

The answer: MYTH. Here's why. Though tryptophan is present in turkey, it is in very low levels compared to other foods such as chicken or even cheese. But none of these really make you tired - have you ever found yourself REALLY exhausted after eating some cheese? No… because there are other amino acids (proteins) that compete with the metabolism of tryptophan that may inhibit some its effects. Also, you never JUST eat a ton of turkey (going back to the original question), so the other foods you eat slow down the metabolism of this amino acid and allow it to enter the body slowly and in small doses. Tryptophan usually needs to be consumed on an empty stomach in order to feel the effects.

Let's talk quickly about the effects of tryptophan - it is an amino acid (protein) that gets metabolized in the body to produce niacin (a B-vitamin), serotonin, and melatonin. The combination of these has been shown to cause a calmness/sleepiness effect, but again, only when on an empty stomach and in large doses.

So what makes you sleepy on Thanksgiving? In fact, a few things. Firstly, the amount of food eaten on a typical Thanksgiving meal is enough to make anyone tired. This goes back to basic nutrition principals of eating smaller portions. Thanksgiving dinner is an exaggerated example of why eating large meals is not what is best for the body - you get tired because your body is spending its energy metabolizing all of the food you just shoveled into your body. Also, this meal is usually rich in carbohydrates, leaving the amino acids that normally compete with tryptophan to go into the muscles with the release in insulin (in order to handle the glucose load from the carbohydrates you just consumed), causing a relative increase of tryptophan in the bloodstream (but is still not enough to make you tired on its own). The COMBINATION of all of these events together is what makes you sleepy, but I guarantee if you ate normal sized portions following the MyPlate concept (half veggies, quarter carb, quarter protein), you wouldn't be tired at all and might even be up for a game of outdoor touch football with your siblings.

So take that as you will, but the fact is, TURKEY DOES NOT MAKE YOU TIRED.

Hope this helps. Happy eating!nv