How Sugar Impacts Sleep


Most people have learned about the importance of a healthy diet, yet many still indulge in the occasional late-night sugar craving. However, eating sugar may contribute to poor sleep. If you're consistently waking up groggy instead of energized, there's a chance that your sweet tooth could be part of the problem.

How Does Sugar Affect Sleep?

A diet high in sugar and carbohydrates has been shown to make people feel sleepy and fall asleep faster (1), but it also causes poor sleep quality (2) and more nighttime awakenings (3). There's no clear evidence that sugar causes the sugar high (4) that's been blamed for hyperactivity in children, although it's possible that some children (5) may react to sugar this way.

Sugar is the simplest type of carbohydrate (6). Other types of carbohydrates include starches and fibers, which are considered complex carbohydrates because they are made of multiple simple sugars. Many studies on diet and sleep group together the effects of all three carbohydrate types, rather than look at sugar's specific impact. Nevertheless, examining the effects of carbohydrates on sleep helps shed some light on how sugar might affect sleep.

High-carbohydrate diets elevate levels of tryptophan (7), an amino acid that promotes sleep. Sugar also suppresses orexin (8), a neurotransmitter responsible for promoting alertness. Although sugar makes you sleepy, this reaction seems to be offset by poor sleep quality later in the night, including difficulty maintaining sleep (9) and a lower proportion of restorative deep sleep.

Some researchers have proposed that a high-carb diet with a larger percentage of simple sugars may provide more readily available energy. Faced with more energy to burn, the brain spends less time in deep sleep and more time in rapid eye movement (REM) sleep, which is the sleep stage that uses the most energy. As a result of not getting enough deep sleep, you may wake up feeling unrefreshed.

Eating too much sugar may also contribute to inflammation (10), which can have a negative impact on sleep (11).

Are Certain Types of Sugars Better than Others for Sleep?

Not all sugars are created alike. Consuming more added sugars (12) leads to shorter sleep times (13), while eating more fruit (14) tends to go hand-in-hand with longer sleep times. A few studies have also found a strong link between sugary drinks and poor sleep, although sugary drinks often contain caffeine (15), which can impact sleep quality on its own.

Since most studies on diet and sleep have been observational, researchers have been unable to definitively pinpoint whether poor sleep leads to cravings for sugary foods, or whether sugary foods affect sleep.

How Does Sleep Affect Diet?

Sleep deprivation alters the brain's reward system (16), making people more likely to indulge in foods that are high in sugar and fat (17).

People who don't receive sufficient amounts of sleep are also more likely to consume more calories overall (18), eat the bulk of their food later in the day, and favor snacks (19) over proper meals. Conversely, extending sleep (20) and maintaining a regular sleep schedule (21) are associated with healthier diet choices.

Over time, the link between poor sleep and unhealthy food choices can have negative consequences for health. Long-term sleep deprivation affects the body's ability to regulate blood sugar (22) and is considered a risk factor for obesity, type 2 diabetes, and heart disease.

What Can You Eat for Better Sleep?

Following a healthy and balanced diet low in refined sugar, salt, and saturated fats can increase energy levels during the day and help you sleep better at night.

Vitamins and nutrients that are especially beneficial for sleep include vitamin D, vitamin C, calcium, and selenium. You can find these vitamins and nutrients in foods like nuts, grains, dairy products, seafood, meat, fruits, and vegetables.

If you're craving a late-night snack, there are certain foods said to promote sleep by boosting levels of melatonin, the sleep hormone. Foods that may be sleep-inducing include milk, kiwifruit, and tart cherries. A bedtime snack high in fiber-rich complex carbohydrates (23), such as nuts, may also contribute to more restorative sleep.

For the best sleep, include a variety of foods (24) in your diet. Incorporating a balance of proteins (25), carbohydrates, and healthy fats in every meal can help keep your blood sugar and energy levels more stable. Give your sleep an extra boost by eating a well-rounded breakfast, exercising regularly (26), avoiding sugar before bed, and drinking plenty of water.

It may be difficult to kick the habit of reaching for sugary treats when you're tired. However, each day of proper eating brings you one step closer to better sleep and helps you wake up feeling more energized.


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