Why Eating Turkey Doesn’t Make You Sleepy

Each Thanksgiving, some well-meaning but misinformed person claims that there's a special substance in turkey that makes you sleepy. This person (typically a relative) also believes that eating extra protein makes your muscles grow bigger, and that you lose most of your body heat through your head. But don't blame the turkey you just ate if you start nodding off at the dinner table. Your dinner guest's ability to speak like paint dries may be the problem.

Sacred Cows and Birds

This year, I've written several blog entries that debunk urban legends. Contrary to popular belief, eating extra protein does not make your muscles grow bigger. Nor do you lose most of your heat through your head. Generally, people don't get too upset when they learn what they knew about these things was wrong. But when I told my colleagues that I planned to blog about how eating Thanksgiving turkey (or any turkey) doesn't make you sleepy, there was a lot of squawking. So for everyone who didn't believe me, this one's for you!

Turkey and Tryptophan

It's true that turkey contains tryptophan, an amino acid with a documented sleep-inducing effect. Yet the amount of tryptophan eaten during a huge Thanksgiving dinner is still too small to make a significant difference in one's energy levels. In order to produce a truly sleepy effect, tryptophan needs to be taken on an empty stomach and without any other amino acids or protein. In addition, many other foods (such as beef, soybeans, chicken, pork and cheese) actually contain comparable or higher levels of tryptophan than turkey.

So why do people feel so lazy and lethargic after a Thanksgiving meal? This feeling of sedation comes from a combination of several sources. Tryptophan may be found in dietary proteins, but it is the carbohydrate-rich foods on the Thanksgiving table (such as potatoes, stuffing, bread and pie) that trigger the release of insulin, which stimulates competing amino acids into leaving the bloodstream and entering muscle cells. With other amino acids swept out of the bloodstream, tryptophan is more easily able to make its way to the brain to produce serotonin and induce sleepiness.

Feeling Fat and Lazy

Fats also slow down the digestive system, which will give your huge helpings of food time to take effect. It also takes a great deal of energy to digest a large meal. Fats especially take a lot of energy to digest, so the body will redirect more blood there to help out. The body's blood flow is so focused on digestion that you will feel less energetic.

Also, let's not forget one of the main causes of Thanksgiving Day sleepiness that many people fail to remember – alcohol. Thanksgiving isn't New Year's Eve, of course, but most people aren't used to drinking (so much) during the day.

So if you don't want to be a sleepy blob after Thanksgiving dinner, fill up on the turkey, ease up on the carbohydrate-rich and fatty side dishes, limit your alcohol intake, and go outside and play football instead of parking your duff on the couch watching it.

Happy Thanksgiving!

Galina

Resources:

http://www.snopes.com/food/ingredient/turkey.asp

http://www.scambusters.org/turkey.html

http://en.wikipedia.org/wiki/Tryptophan#Turkey_meat_and_drowsiness

http://chemistry.about.com/od/holidaysseasons/a/tiredturkey.htm

http://www.physorg.com/news8453.html

http://www.livescience.com/health/071120-bad-turkey-sleep.html

http://listverse.com/2009/02/15/top-10-common-medical-myths/