So THAT'S Why You Get Sleepy After Eating A Big Meal

After piling your plate full of Christmas turkey, stuffing, mashed potatoes covered in gravy, sweet potatoes and a slice of pie or two, you might want to crash on the couch rather than join the family game of touch football. Though you may have heard that the turkey is to blame for your drowsiness, that isn’t true. 

Instead, a carb-heavy meal and an exhausting week of preparation are more likely the cause, according to doctors. Carbs and sugar from our Thanksgiving favourites convert into melatonin and serotonin, giving us that food coma we all know and love. 

To separate fact from fiction, we turned to experts who could shed some light on why we want to pass out after Thanksgiving dinner. 

The Food Coma, Explained

A food coma ― that sweet, sleepy, slightly stuffed feeling you get after a big meal ― is also known by its medical name, postprandial somnolence. Thanksgiving is the perfect storm for a food coma, according to Dr. Deepinder Goyal, a gastroenterologist at Gastro Health in Orlando, Florida. Goyal explained that consuming sedatives like alcohol, eating foods rich in tryptophan (more on that later) or chowing down on a large meal can all trigger a food coma. 

We feel sleepy because blood is diverted from the brain to the gut to process all that extra food. Dr. Rich Joseph, an attending physician at Brigham and Women’s Hospital in Boston, explained, “The bigger the meal, the more of your blood goes to the gut to aid in digestion. Less blood in the brain, so you feel sleepier. But your actual sleep quality may be impaired by alcohol consumption and indigestion from all the food you ate!”

If you have any co-morbidities, such as sleep apnea or hypothyroidism, these could also contribute to your food coma. 

The Big Myth About Turkey And Tryptophan

Despite the common myth that says otherwise, you can stop blaming your food coma on the turkey. Though the bird contains tryptophan, the amino acid involved in mood and sleep, Dr. Christopher Winter, a neurologist and sleep specialist, argues there isn’t enough to make an impact. He said, “As foods go, turkey is not particularly high in tryptophan. Sleepiness typically comes from high carbohydrate intake and resultant change in blood sugar and insulin levels.”

What is tryptophan? It’s an essential amino acid found in many common foods we eat, including oats, bananas, milk, tuna, cheese and chicken. In the body, tryptophan helps produce melatonin, aka the sleep hormone. It is also sold as a supplement to aid with insomnia and sleep disorders, but they contain about 20 times the amount of tryptophan that’s in your Thanksgiving turkey.  

Carbs Are The Real Culprit

The mashed potatoes, sweet potatoes, stuffing, rolls and pie are loaded with carbs, which is likely wreaking havoc on your blood sugar.

“Foods with a higher glycemic index tend to cause more spikes and subsequent crashes in blood sugar,” Joseph said. A blood sugar crash might feel like that afternoon slump when you can’t focus on work, or it can just make you irritable and tired. 

Dr. Erica Jansen, a nutritional epidemiologist at the University of Michigan, explained, “Simple carbohydrates make it easier for tryptophan to cross the blood-brain barrier, so it may be that the combination of turkey and carbs causes sleepiness instead of just turkey alone.” 

Another myth is that carbs will improve our mood: A meta-analysis in Neuroscience & Behavioural Reviews found that folks who ate simple carbohydrates experienced fatigue and less alertness after an hour and showed no positive effect on mood. Don’t ditch the potatoes just yet. 

Adding some fibre ― a salad, acorn squash, roasted Brussels sprouts ― and piling the plate with satiating protein can help counteract some of the lethargic effects of the carbs. Joseph told HuffPost, “If it is a big meal consisting of various carbs, fats and proteins, it will likely cause less of an aggressive spike in blood sugar, especially if you eat the proteins and fats (i.e., the turkey and gravy) before the sweet carbs (i.e., candied yams).”

Other Potential Factors: Alcohol And Stress

A couple of glasses of Chardonnay with your meal (or a couple of beers while watching the game) can also help you relax and induce that sleepy feeling, though Winters cautions that alcohol can have a negative effect on sleep quality. If you choose to drink, imbibe earlier in the day or at least a few hours before bedtime. Jansen said. “In a similar manner, alcohol intake may improve mood in the moment but can lead to lower mood later on, at least partially through the decrements in sleep quality.” 

Stress from flight delays, traveling with kids or family tension can all contribute to poor sleep leading up to Thanksgiving. Once dinner is over, the pressure around Thanksgiving tends to ease up, and the tiredness might just be catching up with you, Jansen explained.