Do you believe in the holiday food coma?
Many people do. Turkey, a mainstay on the dinner table this time of year, contains tryptophan, which is widely believed to be responsible for the uncontrollable yawning and sudden naps that often occur after big family gatherings.
“Tryptophan is an essential amino acid needed to make serotonin, a hormone that has many functions in our body, including balancing mood and sleep,” says sleep specialist Dr. Raj Dasgupta, an associate professor of clinical medicine at the University of Southern California’s Keck School of Medicine.
“The by-product of the tryptophan-to-serotonin process is melatonin, another hormone that regulates our sleep cycle,” he said. “Our bodies don’t naturally produce tryptophan, so we have to get it through the food we eat.”
However, besides turkey, many foods 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 one of the “feel-good” hormones, which can calm and relax the body. However, we don’t consume nearly enough turkey during a holiday smorgasbord — even going back a few seconds — to create the amount of serotonin needed to make us sleepy, said Steven Malin, an associate professor in the department of kinesiology and health at Rutgers University in New Jersey.
To get the amount of tryptophan needed to induce a food coma, he said, we’d need to eat about 8 pounds of turkey meat — about half the size of a typical bird meant to feed a crowd. The United States Department of Agriculture recommends planning for a 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 make us sleepy,” Malin said.
So you can’t just blame the gobbler on your table for your sudden drowsiness, said 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 drowsy after a big meal, it’s probably because we’re not getting enough sleep in the days leading up to the big event and finally being able to relax after dinner is over.”
Overeating in general is also a big culprit for the fatigue one feels after eating, Dasgupta said.
“Think of all the delicious side dishes around the turkey center, like sweet potato pie, casseroles and yummy desserts,” he said. “These tasty dishes are high in carbohydrates that also contribute to post-meal drowsiness.”
Another reason why you feel sleepy after a meal is a change in blood flow from the head to the digestive system.
“Eating a big celebratory dinner increases blood flow to the stomach to help digest the meal, which results in less blood flow to the brain, leaving you tired and ready for bed,” Dasgupta said.
And don’t forget the impact of holiday drinking. 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 afternoon ball games.
“Let’s face it, it’s the holidays and there might be some family stress or travel fatigue, so you might have been drinking more than usual,” Dasgupta said. “Alcohol slows down your brain and relaxes your muscles, so you’ll probably feel drowsy after a few drinks.”