BY GEORGE: Are You Tired After A Large Meal?

One belief is that heavy consumption of turkey (as for example in a Thanksgiving feast) which has been attributed to high levels of tryptophan contained in turkey. However, while turkey does contain high levels of tryptophan, the amount is comparable to that contained in most other meats.  The post-meal drowsiness after Thanksgiving dinner may have more to do with what else is consumed along with the turkey and, in particular, carbohydrates.  It has been demonstrated in both animal models and humans that ingestion of a meal rich in carbohydrates triggers release of Insulin.  Through a complex system of enzyme release, hormone balances, and digestive processes, the data suggest that "feast-induced drowsiness"—and, in particular, the common post-Christmas and North American post-Thanksgiving dinner drowsiness—may be the result of a heavy meal rich in carbohydrates, which, via an indirect mechanism, increases the production of sleep-promoting melatonin in the brain.

An essential amino acid found in a wide variety of foods, tryptophan plays a small role in regulating sleep, but the amount in turkey is minimal. In addition, the body self regulates absorption of tryptophan, so even if you ate a large amount of foods containing it, your body would adjust, minimizing tryptophan’s effects. Tryptophan also can be found in eggs, cheese, fish, nuts and soy products, among others.

Tryptophan is one of 20 amino acids found in foods and can be converted in your brain to the neurotransmitters, serotonin and melatonin.  Since both of these compounds play an important role in regulating sleep, it seems quite logical that tryptophan has always been fingered as the sleep-inducing culprit behind the Thanksgiving Day nap.  But if you look a little further into the science (or lack of) behind this folklore, you will soon realize that this tryptophan theory just doesn’t make any physiological sense.