The Relationship Between Carbohydrates and Sleep

When thinking of carbohydrates, many of us tend to conjure feelings of increased energy levels—at least for the short-term—which is why we love to reach for a big handful of crackers or something sweet when that 2 p.m. slump starts to rear its head. (It’s effective.)

Brierley Horton, MS, RD, co-host of the Happy Eating Podcast, says that whenever we eat carbs, our bodies break them down into glucose. This addition of glucose into the bloodstream creates a burst of energy, as Horton explains that glucose fuels the cells in our bodies. “Plus, it’s the brain’s preferred energy source,” she adds. However, Horton notes that the “type” of boost you may experience is dependent on the source of carbohydrate you’re reaching for.

“The type of carbs you eat may influence how you feel,” says Horton. “For instance, a spoonful of sugar or a very refined white carbohydrate, like ultra-processed white bread or chips, will get into your bloodstream pretty quickly, which then causes your pancreas to release more insulin. Insulin is how your body ‘uses’ glucose for energy; without it, you wouldn’t be able to get glucose into the cells of your body that need it. The quick spike in insulin then brings down your blood sugar quickly, which can cause you to ‘crash’ or feel a bit sluggish.”

That said, Horton says that if you’re opting for those more well-rounded complex carbohydrates that also come packaged with fiber, vitamins, minerals, and possibly even a bit of protein (think: fruit, vegetables, whole grains, legumes), these other nutrients will slow down the blood sugar spike, creating more steady energy levels throughout the day. And interestingly enough, research shows that the consumption of complex carbohydrates could even be a key to promoting better sleep.

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What the research tells us about carbohydrates and sleep

Horton says that there has been some interesting research in the past few years looking at carb-rich meals and snacks and their associations with improved sleep quality. A 2022 review of research conducted by the University of Chicago and Columbia University analyzed 20 studies on diet and sleep quality and found that people who followed a Mediterranean-style diet that’s rich in fiber, fruits, vegetables, and other anti-inflammatory foods—all sources of complex carbohydrates—experienced the best sleep quality overall.

Horton also touts one 2020 study as part of the Women’s Health Initiative that found people who consume diets that prioritize high-fiber carbs that are lower on the glycemic index (generally, complex carbohydrates) were less likely to experience insomnia and enjoy better sleep quality overall than people whose carbohydrate intake came from more highly processed sources. She notes that not only the type of carbohydrates mattered here, but also the timing. “When you eat the meal matters,” Horton says. “Finishing eating at least three hours before bedtime is what the study authors recommended, as eating later showed to increase the number of awakenings in the middle of the night.”

“When you eat the meal matters,” Horton says. “Finishing eating at least three hours before bedtime is what the study authors recommended, as eating later showed to increase the number of awakenings in the middle of the night.”

Also, there are many complex carbohydrates that serve as excellent sources of sleep-promoting nutrients such as melatonin, magnesium, and tryptophan. Some of those top sleep-enhancing foods include brown rice, oats, bananas, cherries, yogurt, and chickpeas, if you’re really looking to get the most bang for your buck.

The bottom line on carbohydrates and sleep

While all of this is great news for anyone who has shunned carbohydrates at dinner time for fear that it would have a negative impact on their sleep, Horton is careful to manage expectations. “While incorporating complex carbs on your plate, along with appropriate amounts of protein and fat, could be useful for promoting satiety and helping us improve our sleep, this is not a magic bullet for securing sweet dreams,” she says. And while most people could benefit from having a serving of fiber- and mineral-rich complex carbs at dinnertime, certain populations may not tolerate them as well.

“Gosh, I wish food could have this much of an effect on us, but carbs, truthfully, aren’t powerful enough to leave you struggling to stay awake or struggling to stay asleep,” Horton says. “That said, if you suffer from reflux, and you’ve overeaten too close to bedtime, you might struggle to fall asleep because lying down could be uncomfortable.”

“Gosh, I wish food could have this much of an effect on us, but carbs, truthfully, aren’t powerful enough to leave you struggling to stay awake or struggling to stay asleep,” Horton says.

Like just about everything else in life, securing proper nutrition and sleep is all about balance. Horton emphasizes that the research is not license to opt for a super high-carb meal at dinnertime, as other studies show that diets that prioritize protein are also important for a good night’s sleep. She says to consider the quality of your carb sources, pair them with other nourishing whole foods, and make sure you’re not eating too close to bedtime to prime your brain (and the rest of your body) for sweeter dreams.