Every year at Thanksgiving, most of us engage in an annual rite of passage: stuffing ourselves mercilessly with turkey, cranberry sauce, stuffing, and pie. Not a bad way to spend a Thursday.  Once again a familiar piece of nutritional reasoning is looping through your mind. It goes like this: Turkey is a rich source of the essential amino acid tryptophan, which our bodies need to build certain kinds of proteins. Tryptophan also is a precursor to serotonin, used to make melatonin, a hormone that helps regulate sleep. Therefore, eating a lot of turkey will make me sleepy while watching football.

Despite how perfectly sound each link in that chain of logic may appear, the conclusion is absolutely false.

“Turkey doesn’t make you sleepy,” said Kim Sasso, a registered and licensed dietitian who spoke to a Loyola University Health System press officer.

Yes, it’s true your holiday bird contains tryptophan. L-tryptophan is an essential amino acid. The body can't make it, so diet must supply tryptophan. Amino acids are building blocks of proteins. Foods rich in tryptophan include, you guessed it, turkey. Tryptophan is also found in other poultry, meat, cheese, yogurt, fish, and eggs, contain the amino acid at comparable levels. In fact, the humble soybean and cheddar cheese both contain more tryptophan, gram for gram, than turkey. As Sasso explained, no matter how much turkey you eat, it simply won’t be enough — after breakdown, metabolism, and transfer within your body — to have a real impact on your brain and cause sleepiness after your holiday meal.

So what does make you sleepy on Thanksgiving?

Eating too much in general, says Sasso, along with “the stressful hustle and bustle of the holiday, travel schedules, alcohol indulgence, and cooking tasks.”she continues "When people overeat food, the digestion process takes a lot of energy. Don't incriminate the turkey that you ate, incriminate the three plates of food that you piled high."

At least then you'll have a good excuse to lay down and take a nap.

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