Here's the thing about turkey: Everyone knows that turkey contains tryptophan, and everyone knows that tryptophan will leave you snoring on the sofa. Well, at least we get one out of two correct. Let's break it down.
Yes, turkey does contain tryptophan. But, then, so does cheddar cheese. In fact, an ounce of cheese contains more tryptophan than an ounce of turkey — and we've yet to hear anyone complaining how tired they are after ordering the cheese plate [source: Wanjek].
Tryptophan is an amino acid your body uses as a building block for producing serotonin, a neurotransmitter that helps to regulate your mood, your appetite and your sleep cycle, in addition to melatonin, a hormone that also regulates sleep. It does play a role in making us sleepy, but here's the thing: You're not ingesting enough tryptophan, nor does enough of it reach your brain after a meal — even a big holiday meal — to overtake you with the urge to nap [source: Young].
As a sleep aid, tryptophan is thought to work most effectively when taken as a supplement on an empty stomach — and in much higher doses than you could eat, even with Thanksgiving seconds (and thirds). While a 4-ounce (113-gram) serving of turkey contains 350 milligrams of tryptophan, the supplements popular in the 1980s contained levels as high as 2,000 milligrams [source: Mikkelson]. But a better sleep-aid snack than cheddar or Swiss is one that contains 1 ounce (30 grams) of carbohydrates [source: Zamosky].