Thanksgiving Myth: Turkey Makes You Sleepy

There are a couple of myths told each year at my house on Thanksgiving. One is that Uncle Lou will finally get the hint by Friday afternoon that he's overstayed his welcome and will leave without swiping most of the leftovers. The other is that there's a natural chemical in turkey called tryptophan that makes you sleepy after the Thanksgiving meal.

While the first myth stems from wishful thinking, the sleepy-turkey myth lingers around each year because it sounds so logical.

Alas, it is only marginally true. What's making you sleepy after Thanksgiving dinner is any combination of booze, bad conversation and a carbohydrate-heavy meal, but not the turkey itself.

The tryptophan trip

Tryptophan is an essential amino acid crucial for good health. Human bodies need tryptophan to build certain kinds of proteins. There is a sleep connection, though. The body uses tryptophan in a multi-step process to make serotonin, a neurotransmitter in the brain that helps regulate sleep.

Turkey does have tryptophan. But all meat has tryptophan at comparable levels. Cheddar cheese, gram for gram, has more. While cheddar isn't the most exciting cheese in the cheese cellar, no one connects it with sleep. Turkey gets singled out for no other reason than being eaten during the biggest meal of the year.

In essence, big meals with any food containing tryptophan can cause sleepiness. The real culprits are all those carbohydrates from potatoes, stuffing, vegetables, bread and pie. The massive intake of carb-heavy calories stimulates the release of insulin, which in turn triggers the uptake of most amino acids from the blood into the muscles except for tryptophan.