Does Sugar Keep You Awake? The Relationship Between Sugar and Your Sleep

Long Story Short

• Yes, sugar can keep you awake at night. Studies show that ingesting more sugary and ultra-processed foods is associated with worse sleep. (1)
• If the sugar you consume before bed also contains caffeine, like in a coffee drink or piece of chocolate, you may experience further negative impacts on your sleep quality.
• Eating within 3 hours of bedtime is positively associated with waking up more during the night and a shorter sleep duration. (2)
• The American Heart Association recommends limiting added sugars to no more than 6 percent of total daily calories, or 6 and 9 teaspoons (25 and 36 grams) for women and men, respectively. (3)
• While enjoying an occasional sweet before bed won’t harm your health, regularly consuming sugary foods and drinks at night can negatively impact overall health and sleep quality. 

There’s plenty of data showing that diets high in sugary, ultra-processed foods — and low in nutrient-dense foods — can hurt our health, and we know eating a high-sugar diet can also impact our sleep. (4)(5)(6) But does sugar keep you awake when you indulge in that sweet little midnight snack? Here’s why you might consider swapping chocolate chips for berries before bedtime, or at the very least, pairing them together if you’re having trouble sleeping. 

Note: The content on Sleepopolis is meant to be informative in nature, but it shouldn’t be taken as medical advice, and it shouldn’t take the place of medical advice and supervision from a trained professional. If you feel you may be suffering from any sleep disorder or medical condition, please see your healthcare provider immediately. Additionally, restrictions and regulations on supplements may vary by location. If you ever have any questions or concerns about a product you’re using, contact your doctor.

How Does Sugar Affect Sleep? 

Consuming too much added sugar can affect your energy levels, disrupt hormonal balance, cause inflammation, and trigger irregular patterns of sleep, even promoting insomnia. (7)(8)(9) That’s because sugar has a big impact on multiple important body functions — more on that below. 

It’s important to distinguish between natural sugars — found in something like an apple — and added sugars, which are used as sweetening agents in things like soda or birthday cake. In addition to sugar, the apple contains fiber, vitamins, minerals, antioxidants, and other important nutrients. A can of soda, however, doesn’t contain much else in the way of beneficial nutrition and is digested quickly, having noticeable effects on your body — including your sleep quality.

From a broader perspective, there’s plenty of research to back up the fact that sugar meddles with your sleep quantity and quality. Several studies have found that a higher sugar intake from less healthy beverages and food sources has a direct negative impact on sleep quality. (10) (1)

First, high-sugar, refined carb sources that are low in fiber and protein are rapidly digested and absorbed, leading to spikes in your blood sugar and insulin levels. These fluctuations can make it more difficult to get good-quality sleep. (11) Your blood sugar levels then decline just as quickly, as your body releases the hormone insulin to move glucose from your blood into your muscle, fat, and liver cells, where it can be used for energy or stored. (12) In contrast, complex carbs, such as fruits and beans, are more slowly digested, leading to a more steady rise and fall in blood sugar and insulin levels. (13)

Alyssa Pacheco, registered dietitian from The PCOS Nutritionist Alyssa, adds that “the rapid increase in blood sugar [from eating high-sugar foods] can stimulate your brain and make it more difficult to fall asleep. The blood sugar fluctuation can cause increased feelings of hunger and thirst that may wake you up and disrupt your sleep.” (14)

Additionally, insulin resistance, a common result of a high-sugar diet, can affect how your body regulates blood sugar during sleep, potentially leading to restless nights. Studies show that people with insulin resistance tend to have poorer sleep quality compared to people who don’t. (15)

When your body is insulin resistant, it means your blood sugar levels aren’t responding appropriately to insulin release, triggering more insulin release and prolonged high blood sugar. Note that having insulin resistance doesn’t mean you have type 2 diabetes, but could eventually lead to its development. (16)(17)

In some cases, high sugar intake may contribute to sleep apnea or snoring, as it can increase inflammation and mucus production in the body in a way that could worsen breathing. (18) For example, sugary foods and drinks, such as cakes, soda, and cookies, are a source of advanced glycation end products (AGEs), which can contribute to oxidative stress and inflammation and worsen sleep apnea. (19)

So, does sugar keep you awake? It certainly can, but of course, everyone is different. Overall, if you’re struggling with sleep, reducing your sugar intake (especially later in the day) may be a good intervention. Instead, focusing on a balanced diet rich in whole and minimally processed foods low in added sugars can help support a healthier sleep cycle and overall wellness. (20)

How Long Does Sugar Keep You Awake? 

While consuming sugary foods or beverages can affect everyone differently, there’s a good chance sugar could keep you awake longer than you like. Simple sugars, like those found in candy or soda, are digested quickly and result in a more immediate spike in blood sugar. This is because these types of foods don’t contain much (if any) fiber, which would slow down their digestion. These dramatic fluctuations may make you feel crummy (some people get shaky, for instance) and have trouble finding a calmness before bed. (21)

On the other hand, foods that contain fiber (often categorized as “complex carbohydrates”), like whole grains, fruits, vegetables, nuts, seeds, and legumes, are digested and release sugar into your bloodstream more slowly. This leads to a more gradual rise and fall in your energy (with more stability overall) which may be more conducive to getting a better night’s sleep — basically, the way high-fiber foods are digested helps you avoid dramatic spikes and falls in blood sugar that may otherwise keep you awake. (22)

How Long Before Bed Should I Stop Eating Sugar? 

A general guideline is to stop eating at least 2-3 hours before bedtime to allow your body time to stabilize blood sugar levels and avoid the stimulating effects of sugar. This refers to all foods, not just the sugary ones. (23) When you eat something sugary too close to bedtime, the subsequent blood sugar and insulin spikes can make it harder to fall asleep and stay asleep. 

However, everyone is different and some people may feel better and sleep better when they have a snack closer to bedtime. Your calorie and nutrient needs depend on many factors, so it’s best to take a personalized approach when it comes to meal timing. Qianzhi Jiang, PhD, RDN, LDN, and owner of The Nutrition Changer, says, “A light snack at bedtime may be helpful to prevent low blood sugar and help people fall asleep faster.”

Dana Sowards, registered dietitian, says, “We know that having added sugar alone (without protein, fat, or fiber) can cause a drastic spike in blood sugar and a blood sugar crash on the other side, so if having a high-sugar snack before bed, an individual may wake in the middle of the night feeling hungry or thirsty.” She says that if you want something with sugar toward the end of the day, it’s probably best to have it during the tail-end of dinner to prevent such a dramatic blood sugar spike. 

Sugar by the Gram

Odds are, if you did a little digging into the sugar content of your favorite snacks and beverages, you might be surprised with what you find. We did a little research on some favorite snack-time treats, and it was eye-opening, to say the least. 

Below is the total sugar content of some popular foods and beverages: 

The Results

Unsurprising to any savvy sweet-toothed readers, a Starbucks Mocha Frappuccino tops the leaderboard with a whopping 51 grams of sugar per serving — more than double the recommended daily amount. (24) While it might be tempting to think that a cup of yogurt or a glass of chocolate milk (both of which are often considered to be healthier food choices) wouldn’t have packed such a punch in terms of sugar content, both items are surprisingly high up on the list with 18 grams and 24 grams per serving respectively. (25)(26)

How Much Is too Much? 

The American Heart Association recommends limiting added sugars to no more than 6 percent of total daily calories, or 6 and 9 teaspoons (25 and 36 grams) for women and men, respectively. (3) While the warnings about processed foods are usually loud and clear, remember that the added sugars in ultra-processed snack foods, desserts, and sodas are not the same as the natural sugars found in healthy foods like fruits (which also contain fiber, vitamins, minerals, and antioxidants).

So What Should You Snack On? 

Good bedtime snacks include fiber-rich foods with a low glycemic index, meaning they aren’t digested super quickly and keep your blood sugar fairly stable. They should provide complex carbohydrates, healthy fats, and proteins to prevent going to bed hungry without keeping you up.

Jiang recommends foods high in magnesium, melatonin, tryptophan, and/or zinc as these nutrients can enhance relaxation and melatonin production. For example, she likes a handful of no-salt-added nuts. (27)(28)(29)

Pacheco said, “An apple with peanut butter is a great choice. This snack duo combines fiber with healthy fats and protein to create more stable blood sugar levels, which can contribute to better sleep quality.” She continues, ”The peanut butter also has tryptophan in it.”

Sowards is a sports dietitian who works with endurance athletes. She says, “I typically recommend Greek yogurt or cottage cheese before bedtime for a little protein, calcium, and magnesium before bed.” 

We also asked some other registered dietitians for their favorite foods to help you sleep. 

Bonnie Lau, registered dietitian from The Asian Dietitian recommends pineapple, oranges, bananas, and kiwi fruit, or tart cherry juice. (30) Pair a small portion of these with yogurt or another protein food to prevent a blood sugar spike. “Omega-3 is also found to help improve sleep quality,” she notes, so you could consider tuna or salmon on crackers. (31)

Alexandria Hardy, RDN, LDN told Sleepopolis, “My favorite low-sugar bedtime snack is a banana with nut butter. It offers protein and carbohydrates to keep blood sugar levels stable; nut butter can also offer healthy fat to help keep you full overnight.” 

“I recommend topping sliced or silvered almonds on plain Greek yogurt before bedtime as a low-sugar snack choice,” says Patricia Kolesa, MS, RDN of Dietitian Dish LLC, noting that they’re good sources of magnesium and calcium to support rest. If this doesn’t suit your fancy, consider something like Strawberry-Chocolate Greek Yogurt Bark or hopping on the Cottage Cheese Ice Cream trend for a high-protein, satisfying nighttime snack.

FAQs

The Last Word From Sleepopolis 

Sugar is certainly a sweeter part of life (and that’s okay!) but it’s important to know when eating too much of it, particularly from ultra-processed foods and beverages, is negatively affecting your health. If you’ve noticed more trouble winding down for the night, falling asleep, or even staying asleep, it’s possible that sugar may have a hand in it. Although sleep is multifaceted, consider how you can reduce sources of added sugar in your diet and see if it helps you rest easier.

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Pacheco, Alyssa. Personal interview. September 30, 2024. 

Lau, Bonnie. Personal interview. September 30, 2024. 

Jiang, Qianzhi. Personal interview. September 30, 2024.

Sowards, Dana. Personal interview. September 30, 2024.

Hardy, Alexandria. Personal interview. September 30, 2024.

Kolesa, Patricia. Personal interview. September 30, 2024.