Urban Myth Busted In Time For Thanksgiving: Turkey Does Not Make You Sleepy

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It's irrelevant whether you like turkey or not because someone is going to be handing you a plate of it very soon. And after the meal, there's a good chance that you'll get sleepy. But will the cause of your drowsiness be the turkey, the booze, or your brother-in-law's tedious commentary about his golf game?

With Thanksgiving around the corner, there are a few certainties:

  • The Cowboys and Lions will both play. This year they will probably both lose.
  • You will ask yourself why you drove 200 miles to see relatives, some of whom you can't stand.
  • You will eat too much and get sleepy.
  • You will blame this on the turkey since it supposedly contains a whole lot of tryptophan, which is supposed to make you sleepy. It doesn't.
  • Your drowsiness is a product of the football, the relatives, or most likely, both.

But, as is often the case with urban myths, there is a kernel of truth in here someplace. And, on a biochemical level, there is at least a plausible rationale. In a two-step process, tryptophan is converted in the body to serotonin, and then to melatonin an endogenous sleep-regulating hormone. So, it is not absurd to postulate that if you eat a food that contains a lot of tryptophan, then you might get sleepy.

But, it's wrong.

Tryptophan is one of the 20 amino acids that are converted into proteins by DNA in humans. Proteins are enormous chains of amino acids. There are about 100,000 of them in a human, and they are responsible for almost every structure and biochemical reaction in the body. Proteins can be as small as 44 amino acids linked together, or as large as 34,000.

When protein is consumed, it breaks down to its corresponding amino acids in the gut, so the 20 of them will be released. This is where the tryptophan in turkey comes from.


There would be at least two requirements for turkey to really make you sleepy:

  1. It would have to contain a lot of tryptophan.
  2. The tryptophan would have to be converted into melatonin quickly and in sufficient quantity.

Number two is irrelevant because number one is wrong. Turkey contains the same amount of tryptophan as plenty of other meats. There is nothing special about it.

Rather, Thanksgiving sleepiness has been attributed to a number of factors, including overeating and too much alcohol. However, this is not universal. I don't especially like turkey, so I am unlikely to eat too much of it. And, I don't drink either.

Must be the relatives.