Love sandwiches, but feel sleepy afterward? There are reasons why you may find yourself feeling tired after eating bread. Depending on the kind of bread you consume (white vs. whole grain, etc.), that oh-so-good dough could make you sleepy as the result of either glycemic load or gluten — or both.
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Gluten Got You Tired?
Gluten is a family of proteins that, per the Institute of Food Science & Technology, is present in wheat and related grains (like rye and barley). It's what gives the dough its elastic, stretchy composition, making it easier to bind together.
But, for some, gluten in products like bread can cause dietary distress in the form of celiac disease. According to the Celiac Disease Foundation, about 1 in 100 people worldwide are affected with this autoimmune disease in which gluten intake creates an immune response in the body that attacks the small intestine. And, according to a May 2015 review published in Alimentary Pharmacology & Therapeutics, the milder form of gluten intolerance — called gluten sensitivity — affects up to 13 percent of people as well.
"A gluten sensitivity or reaction can happen anywhere, from within minutes to several days after [consumption]," says Austin, Texas-based clinical nutritionist Lauryn Lax, PhD, OTD. "People who are extremely sensitive to gluten can experience a flare-up or attack upon their immune system for up to six to eight weeks after just one exposure to gluten." And gluten intolerance, like celiac disease, can also cause fatigue, says Harvard Health Publishing.
Swings in Blood Sugar
Beyond gluten, blood sugar could be the culprit — or, specifically the "glycemic load" of the kind of bread you eat. Harvard T.H. Chan School of Public Health explains the variation in the glycemic load of foods via the glycemic index, scaled from 0 to 100 for how quickly a food raises your blood sugar.
Foods with a high glycemic index (white bread, white pasta, candy, etc.) are rapidly digested and raise your blood sugar sharply.
"Bread generally spikes blood sugar, only to send it back down shortly after due to the glycemic impact on the body," Lax says. "If your gut bacteria and body are not absorbing and digesting that energy source, or you don't have enough protein and healthy fat in your diet throughout the entire day, this is more likely."
A December 2016 study published in Appetite found that high glycemic load diets (think foods like white bread) were associated with fatigue, mood disturbances and depression symptoms when compared to low glycemic load diets. While these findings were especially true for people with overweight or obesity, other adults were impacted as well.
Alternatively, lower glycemic index foods are digested slowly and result in a more gradual rise in your blood sugar. These foods include:
- Whole grain bread.
- Bran cereals.
Whole Grains for Whole Health
Making you even more likely to become tired after eating white bread is the quick release of insulin triggered by refined grains, which also prompts the amino acid tryptophan to stay in your blood and enter your brain, according to Cleveland Clinic. As a result, more serotonin is produced, and you feel sleepy.
To combat that need for a nap, adds Cleveland Clinic, you can choose whole grain options to trigger a slow release of insulin, thereby stabilizing blood sugar (and your energy!) and releasing serotonin gradually.
At the end of the day, you don't have to give up bread or your favorite sandwich to prevent the ensuing need to snooze. You can prevent the sleepiness associated with bread by choosing high-fiber whole-grain options, which slow down digestion, and, in effect, keep your blood sugar more balanced, according to the Mayo Clinic — keeping you more energized and sugar crash-free.
Bonus: Whole grains reign supreme on the scale of healthiest grains, adds the Mayo Clinic. When you're choosing your next loaf, remember that a brown bread doesn't necessarily fit the bill. Look for loaves clearly labeled "whole" on the packaging, and check the label to be sure whole grains appear as one of the first ingredients.
- Institute of Food Science & Technology: “Protein: Gluten Formation”
- Celiac Disease Foundation: “What Is Celiac Disease?”
- Alimentary Pharmacology & Therapeutics: “Systematic Review: Noncoeliac Gluten Sensitivity”
- Harvard Health Publishing: “Non-Celiac Gluten Sensitivity”
- Lauryn Lax, PhD, OTD, occupational therapist, clinical nutritionist, Austin, Texas
- Appetite: “Subjective Mood and Energy Levels of Healthy Weight and Overweight/Obese Healthy Adults on High- and Low-Glycemic Load Experimental Diets”
- Harvard T.H. Chan School of Public Health: “Carbohydrates and Blood Sugar”
- Cleveland Clinic: “Food and Mood”
- Mayo Clinic: “Dietary Fiber: Essential for a Healthy Diet”
- Mayo Clinic: “Whole Grains: Hearty Options for a Healthy Diet”