Do you believe in the holiday food coma?
Many people do. A mainstay on the dinner table this time of year, turkey contains tryptophan, which is believed to be responsible for the yawning and sudden sleepiness that is common after large family gatherings.
“Tryptophan is an essential amino acid needed to make serotonin, a hormone that has many functions in our body, including regulating mood and sleep,” said Dr. Raj Dasgupta, associate professor of clinical medicine at Keck University of Southern California. School of Medicine
“The byproduct of the tryptophan-serotonin process is melatonin, another hormone that regulates our sleep cycle,” he said. “Our bodies don’t make tryptophan by themselves, so we have to get it from the foods we eat.”
However, many foods besides turkey contain tryptophan, including cheese, chicken, egg whites, fish, milk, peanuts, pumpkin seeds, sesame seeds, soybeans, and sunflower seeds, according to the National Library of Medicine.
Serotonin is a “feel good” hormone that can calm and relax the body. Even so, we don’t consume nearly enough turkey in a holiday scramble — even if we go back for seconds — to produce the amount of serotonin needed for sleep, said Steven Malin, an associate professor in the Department of Kinesiology and Health. Rutgers University of New Jersey.
To get the amount of tryptophan needed to induce a food coma, he said, we’d need to eat 8 pounds of turkey meat, about half of a typical crowd-serving bird. The U.S. Department of Agriculture recommends one pound of turkey meat per person when preparing a holiday meal.
“Tryptophan from turkey is unlikely to enter the brain and produce enough serotonin to sleep,” Malin said.
So you can’t just blame the eater at your table for your sudden sleepiness, says sleep specialist Kristen Knutson, an associate professor of neurology and preventive medicine at Northwestern University’s Feinberg School of Medicine.
“Turkey doesn’t really make us sleepy,” Knutson said. “If we feel sleepy after a big meal, it might be because we didn’t get enough sleep in the days leading up to the big event, and finally being able to relax after dinner.”
Eating too much is also the main culprit for feeling tired after eating, Dasgupta said.
“Remember all the delicious side dishes that surround the middle portion of the turkey, such as sweet potatoes, casseroles and sweet desserts,” she said. “These tasty treats are high in carbohydrates, which also help with post-meal sleepiness.”
Another reason you feel sleepy after a meal is because of a change in blood flow from your head to your digestive system.
“Eating a large holiday dinner increases blood flow to the stomach to help digest the meal, which results in less blood flow to the brain, leaving you feeling tired and ready for bed,” Dasgupta said.
And don’t forget the effect of holiday drinking either. Many meals served at this time of year are washed down with wine, cocktails and champagne. Then there’s the ubiquitous beer (or two or three) that often accompanies evening ball games.
“Let’s be honest, it’s the holidays and there might be family stress or travel fatigue, so maybe you drank more than usual,” Dasgupta said. “Alcohol slows down your brain and relaxes your muscles, so you’ll feel drowsy after a few drinks.”