Does Sugar Keep You Awake? (Doctor’s Answer)


This article was written by Dr. Babar Naeem (MBBS, MRCPCH) – a licensed and practicing medical doctor – to ensure maximum factual accuracy and unique content.

If you’re struggling with insomnia and you eat a lot of sugary foods, you may be wondering if it’s the sugar that’s keeping you awake.

Excessive sugar consumption can keep you awake and cause insomnia by triggering hypoglycemia – which has been shown in scientific studies to disrupt sleep by triggering the release of stress hormones like adrenaline and cortisol that increase energy and restlessness.

There are several other indirect ways that sugar can keep you awake – as I’ve discussed below, along with 5 steps that you can take to stop sugar from disturbing your sleep.

Related: discover exactly how long these 15 types of coffee drinks will keep you awake.

5 Ways Sugar Keeps You Awake

Does sugar affect your sleep? – Dr Pixie McKenna | Dreams Beds

Below is a full explanation in regards to the top 5 ways that sugar disrupts your sleep:

1: Hypoglycemia Disturbs Sleep

Increased sugar consumption results in low blood sugar at night, which keeps us awake.

When we consume any foods rich in sugar, the glucose levels in the blood rise sharply.

The body produces more insulin to tackle this, and as a result, the breakdown of sugar increases.

When the effect of the food decreases after a few minutes, a decline in blood glucose results, as a high insulin level is still present in the body.

This hypoglycemia results in nighttime awakenings.

Researchers at the Department of Neuroendocrinology, Medical University of Lübeck, Germany mimicked this effect by infusing insulin, for 45 minutes, into healthy individuals.

They were thus able to confirm the awakening effects of nighttime hypoglycemia [3].

Low blood glucose levels also trigger the release of stress hormones – like adrenaline, cortisol, and glucagon – which activate the sympathetic system (also known as the fight or flight response).

Activation of this system increases blood sugar levels, but also causes palpitations, tremors, sleep disturbance, and anxiety.

This mechanism worsens the quality of sleep, and results in insomnia.

Find out if Albuterol can keep you awake here.

2: Increased Inflammation

Sugar is pro-inflammatory, increasing the systemic inflammation that is associated with a poor quality of sleep.

Many of the problems associated with chronic diseases are due to the presence of chronic low-grade inflammation.

Nighttime awakenings, low total sleep duration, and poor sleep quality result from chronic inflammation.

Inflammation directly interferes with the circadian rhythm, resulting in insomnia.

Chronic inflammation also causes fatigue, body pain, depression, and mood disorders.

These problems, in turn, impair the quality of sleep we get [4].

Yeonsoo Kim and his colleagues, while working in the United States, demonstrated that foods high in sugar increase the systemic inflammation that produces inflammatory cytokines which interfere with normal sleep [5].

3: Sugar Disturbs Normal Functioning of the Intestine

Sugar further disrupts quality of sleep by compromising intestinal bacteria and the overall health of the gut.

According to Harvard Medical School, there are about 100 trillion bacteria present in our intestines.

There are about 300 to 1000 different species of bacteria that live in our gut, and these are collectively known as the gut microbiota.

Some of them are good for our health, and others are bad.

They perform many important functions in the body, including the absorption of the nutrients present in our food, the metabolization of drugs, maintaining the structural integrity of the gut, and supporting the immune system.

They also produce vitamin K, which prevents bleeding disorders.

Scientists have recently made the amazing discovery that gut bacteria influence sleep quality.

The diversity of bacteria present in the gut is positively correlated with sleep.

Robert P Smith and his colleagues conducted a study in 2019, and found that increased diversity of gut microbiota resulted in increased time spent in sleep, and improved sleep efficiency.

The researchers believed that this was due to interleukin-6, which is produced by the microbiomes [6].

Further evidence of the correlation between sleep and the gut microbiome is the fact that lack of sleep disturbs gut bacteria.

A diet high in sugar destroys the beneficial bacteria in our intestines.

It kills a bacteria known as the bacteroidetes, and increases the population of another type of bacteria called proteobacteria.

This imbalance of bacteria changes the gut, making it pro-inflammatory.

This modulation of the microbiota has the same effect as the toxins produced by harmful bacteria [7].

James E Gangwisch et al conducted research, and stated that added sugar has a profound effect on sleep, due to changes in the composition of the gut microbiomes [8].

Find out how sleep quality affects blood pressure here.

4: Dental Problems

Dental problems, like caries and gingivitis, which are caused by eating sugar, can result in insomnia.

Our teeth are continuously exposed to a variety of challenges, like foods, drinks, and bacteria.

Nature has devised a mechanism to protect our teeth through the production of saliva.

However, when we eat too much sugar, our teeth get damaged, due to multiple factors.

Eating sugar feeds destructive bacteria, like streptococcus, that destroy the outer coverings on our teeth.

Sugar changes the acidity of the mouth, making it more favorable for the bacteria to grow.

Sugar attracts harmful bacteria to the gums, and destroys the tissues that hold our teeth in place, resulting in gum diseases, like gingivitis.

Some foods, like candies and ice-creams, increase the formation of plaque, which damages the teeth permanently.

In contrast, fruits and vegetables are not only low in sugar, but also have a plaque-removing property.

A study conducted in Brazil revealed that 72.8% of patients with dental problems have trouble sleeping [9].

Moreover, most patients take NSAIDs and other pain killers, which can further worsen their sleep problems.

Discover if sleeping on a full stomach is bad.

5: Sugar Increases Food Cravings

Sugar causes cravings for food that result in awakening to search for food.

The hypothalamus is a part of the brain that regulates appetite and satiety.

When the body is short on calories, the hunger center in the hypothalamus is activated, telling the body to eat, in order to satisfy that hunger.

When the stomach is full, a hormone called leptin is released, which tells the brain to shuts off the eating mechanisms.

As a result, dopamine is released from the hypothalamus, which creates a sensation of satiety and pleasure.

This natural engineering sounds good, except that the sensitivity of this pathway decreases with all the sugar we eat.

This means that when we eat more sugar, the amount of dopamine produced decreases, and the satiety center remains suppressed.

Scientists have recently discovered that this system is activated even before we eat.

Just seeing or smelling a desirable food item can activate the pathway, resulting in the release of dopamine.

The appetite centers are thus unregulated, resulting in a midnight craving for food that disrupts our sleep.

Poor sleep, in turn, increases cravings, and the cycle repeats itself.

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How to Stop Sugar from Keeping You Awake

Try these 5 strategies to stop sugar from keeping you awake at night:

1: Eat Foods that Release Sugar Slowly

Foods that release sugar slowly are beneficial, both for sleep and overall health, in comparison to foods that release sugar rapidly.

The sugar contents of various foods are all different, but this isn’t the only factor that determines the benefits or health hazards caused by a food.

Glycemic index (GI) measures how much the blood glucose level can be increased by certain foods.

Foods can be rated on a scale of 0 to 100 on the GI scale.

Alternatively, also based on the glycemic index, foods can be categorized as one of the following.

High Glycemic Index

Foods with a high glycemic index raise the blood sugar quickly, because of rapid digestion and absorption.

According to the NHS, foods with a high GI include soft drinks, sugar, sugary foods, white bread, potatoes, and white rice.

Medium GI

These are foods with a rating of 56 to 69.

Examples include popcorn, couscous, brown rice, sweet potatoes, etc.

Low Glycemic Index

Foods with a low glycemic index are broken down slowly, and release a sustained amount of sugar into the blood.

Examples include fruits, vegetables, whole grains, and pulses.

With this type of food, you will avoid the risk of midnight hypoglycemia and cravings, and hence prevent sleep disturbances.

Low GI foods also help us sleep better indirectly, by reducing cholesterol levels and aiding in weight loss.

2: Drink More Water

Drinking enough water clears the sugar from the body, prevents dehydration, and curbs midnight cravings.

Water is essential for life, and is required for almost all the systems of the body to function.

Sugar is flushed out of the body after filtration through the kidneys.

Water increases the overall blood volume, making it easier for the body to remove all unnecessary substances, including sugar.

Drinking extra water activates the satiety center of the brain, and curbs midnight cravings for food.

Water contains zero calories, so it also plays a very important role in weight loss, by creating a sensation of fullness in the stomach.

When sugar and other carbohydrates are utilized in the body, heat is produced.

If water intake is insufficient, the body can get dehydrated.

Dehydration is yet another common cause of restlessness and sleep disturbance.

Increased water intake helps us sleep better by keeping us hydrated.

Another important point that I would like to mention here is that when our water intake exceeds a certain amount, we can experience frequent awakenings at night due to the urge to urinate.

Therefore, moderation key.

Experts recommend 125 ounces of daily fluid intake for men, and 91 ounces for women.

About 20% of these requirements can come from food, while the rest should be obtained from water and other beverages.

3: Eat Foods High in Tryptophan

Foods that are rich in tryptophan act as a natural proponent of sleep, and are very useful for patients with sleep disturbance problems.

Tryptophan is one of the essential amino acids that are required to make proteins in the human body.

It is hydroxylated by an enzymatic reaction into a compound called 5 hydroxy-tryptophan (5 HTP), which is used by the body to prepare melatonin and serotonin.

Melatonin is a very important hormone, as it regulates the sleep/wake cycle.

Serotonin plays an important role in sleep, mood, and cognition.

Therefore, foods that are rich in tryptophan are considered natural sleep aides, and should be encouraged for patients with insomnia.

A meta-analysis of 18 studies revealed that tryptophan supplementation shortens night awakenings, and improves quality of sleep [10].

Tryptophan is found in a variety of foods, including milk, oats, eggs, poultry, shrimps, white meat, and sweet potatoes.

4: Avoid Fatty Foods

A high-fat diet is detrimental to sleep, and should be avoided.

Eating a diet rich in fats results in weight gain, which disrupts sleep by causing obstructive sleep apnea and snoring.

Fats stay in the stomach for a long period, because they absorb slowly.

A high fat diet also increases the chances of heartburn and reflux disorder, which can also negatively affect your sleep.

Hypocretin is a chemical that is released by the brain cells to control sleep and arousal.

Excitation of hypocretin (also known as orexin) neurons decreases total sleep time, and increases the wakefulness state.

When orexin neurons are inhibited, our non-REM sleep time increases.

A high-fat diet reduces the sensitivity to orexin, resulting in increased arousal and decreased sleep time.

Examples of high-fat foods include dark chocolate, cheese, fatty fish, butter, cream, olive oil, avocados, etc.

I always recommend that my patients eat a balanced diet that includes complex carbohydrates, like whole wheat, fruits, and vegetables.

5: Brush Your Teeth at Night

Everybody should brush their teeth at least twice a day, especially before going to bed.

This is particularly important for individuals who consume a lot of sugar.

Many food particles and bacteria remain attached to the teeth.

The environment of the mouth is more favorable for bacteria at night, due to decreased movements of the jaw.

Production of saliva also decreases at night, which contributes to dental decay.

Sugar provides an ideal medium for the germs to grow, which is why the incidence of dental problems, like gingivitis, caries, and bad breath, is much more common in people who eat a lot of sugar.

It is not possible to remove 100% of germs from the teeth and gums with a single brushing.

Therefore, regular cleaning of the teeth and gums is recommended.

I recommend that my clients brush their teeth for at least two minutes, twice a day.

A tongue cleaner should be used to clean the tongue, as well.

Flossing should be done to remove food particles that are stuck between the teeth.

Anti-septic mouthwash is the best solution for keeping our gums healthy.

Another mistake that some people make is to eat or drink a snack after brushing their teeth at night.

I always tell my patients to avoid eating at least four hours before bedtime for maximum health benefits.


Sleep disturbances are very common among individuals who consume excessive sugar.

To tackle this problem, people should choose foods that release sugar slowly.

Drinking more water is also recommended, to stay hydrated and flush out the extra sugar through the kidneys.

Diets that are rich in tryptophan are recommended for improving quality of sleep.

Regular brushing and flossing of the teeth are essential for avoiding sugar-related dental problems.


[1] A. Afaghi, H. O’Connor, and C. M. Chow, “High-glycemic-index carbohydrate meals shorten sleep onset,” Am. J. Clin. Nutr., vol. 85, no. 2, pp. 426–430, Feb. 2007, DOI: 10.1093/ajcn/85.2.426.

[2] S.-O. Marie-Pierre, R. Amy, S. Ari, and C. A. Roy, “Fiber and Saturated Fat Are Associated with Sleep Arousals and Slow Wave Sleep,” J. Clin. Sleep Med., vol. 12, no. 01, pp. 19–24, Apr. 2022, doi: 10.5664/jcsm.5384.

[3] S. Gais et al., “Hypoglycemia Counterregulation During Sleep,” Sleep, vol. 26, no. 1, pp. 55–59, Jan. 2003, doi: 10.1093/sleep/26.1.55.

[4] J. M. Dzierzewski, E. K. Donovan, D. B. Kay, T. S. Sannes, and K. E. Bradbrook, “Sleep Inconsistency and Markers of Inflammation   ,” Frontiers in Neurology  , vol. 11. 2020, [Online]. Available:

[5] Y. Kim, J. Chen, M. D. Wirth, N. Shivappa, and J. R. Hebert, “Lower Dietary Inflammatory Index Scores Are Associated with Lower Glycemic Index Scores among College Students,” Nutrients, vol. 10, no. 2, p. 182, Feb. 2018, doi: 10.3390/nu10020182.

[6] R. P. Smith et al., “Gut microbiome diversity is associated with sleep physiology in humans,” PLoS One, vol. 14, no. 10, pp. e0222394–e0222394, Oct. 2019, doi: 10.1371/journal.pone.0222394.

[7] R. Satokari, “High Intake of Sugar and the Balance between Pro- and Anti-Inflammatory Gut Bacteria,” Nutrients, vol. 12, no. 5, p. 1348, May 2020, DOI: 10.3390/nu12051348.

[8] J. E. Gangwisch et al., “High glycemic index and glycemic load diets as risk factors for insomnia: analyses from the Women’s Health Initiative,” Am. J. Clin. Nutr., vol. 111, no. 2, pp. 429–439, Feb. 2020, doi: 10.1093/ajcn/nqz275.

[9] S. L. de A. Lima, C. C. P. Santana, M. A. B. Paschoal, S. M. Paiva, and M. C. Ferreira, “Impact of untreated dental caries on the quality of life of Brazilian children: a population-based study,” Int. J. Paediatr. Dent., vol. 28, no. 4, pp. 390–399, Jul. 2018, DOI:

[10] C. N. Sutanto, W. W. Loh, and J. E. Kim, “The impact of tryptophan supplementation on sleep quality: a systematic review, meta-analysis, and meta-regression,” Nutr. Rev., vol. 80, no. 2, pp. 306–316, Feb. 2022, DOI: 10.1093/nutrit/nuab027.

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