Snooze University

Does Sugar Cause Insomnia? (Here's What the Science Says)

by Dale Cudmore | Updated: Feb 01, 2023

Like any food, eating sugar shortly before sleeping can cause insomnia symptoms.

Part of good insomnia sleep hygiene is not eating at night.

But will eating a high amount of sugar throughout the day impact your sleep?

Research Shows A Link Between Sugar and Poor Sleep

There’s been quite a bit of research that shows a link between consuming high amounts of sugar and having poor sleep quality and insomnia symptoms. It's a particularly cause of insomnia in students.

I’m just going to summarize a few of the more recent and notable studies:

  • “The study concluded that poor sleep quality was significantly related to higher added sugar intake.” (1).
  • In middle school students, short sleep duration was linked to consumption of sugar-sweetened beverages (2).
  • High amounts of sugar (and low amounts of fiber) were associated with greater restlessness while sleeping (3).
  • Short sleep is associated with greater intake of sugary caffeinated sodas (4).

There are many more studies showing similar things.

What that tells us is there’s a definite link between sugar consumption and sleep issues.

However, it doesn’t tell us why sugar causes sleep issues.

SummaryAt this point, research clearly links high sugar consumption to short sleep and lower quality sleep (both symptoms of insomnia).

Why Does Sugar Make Insomnia Worse?

While sugar may not affect everyone’s sleep in the same way, it’s clear that it makes sleep worse for the average person.

But there’s no single reason why.

Instead, research points to multiple effects of sugar that may have negative side effects on sleep. There could still be more that haven’t fully been discovered yet as well.

I’ll summarize the main known reasons why sugar might keep you awake at night.

Sugar Increases Inflammation

Research has shown that sugar increases inflammation in the body.

One study had subjects consume 40-80mg of refined sugar in soft drinks per day (about 2 cans of Pepsi on the high end). In just 3 weeks, inflammation markers rose in all groups in healthy young men (5).


Many studies have determined a link between poor sleep and inflammation (6).

Note that this is a correlation, meaning that inflammation could be disrupting sleep, or vice versa. Either way, it makes sense to try to reduce inflammation.

SummaryModerate to high levels of sugar consumption trigger an inflammatory response in the body, which may cause sleep issues.

Sugar Depletes Magnesium

Magnesium is one of the most important minerals for sleep.

It’s needed for the neurotransmitters that are involved in sleep processes (e.g. GABA) to function properly (7).

But both digesting and using sugars requires a large amount of magnesium.

SummarySugar uses a substantial amount of magnesium, which can cause sleep issues if your magnesium levels become low.

Too Much Sugar Can Lead to Insulin Resistance

It’s not surprising that your blood sugar levels rise after consuming sugar. Your body then releases insulin to remove sugar from the bloodstream.

However, if you consume too much sugar on a regular basis, it can lead to insulin resistance.

Aside from increasing your risk of diabetes, research shows that insulin resistance contributes to short sleep duration and insomnia (8). It's the reason why medication that improves insulin resistance like metformin improves insomnia in diabetics.

It’s not surprising that diabetics are more likely to have insomnia and poor sleep quality, although insulin resistance isn’t the only factor at play there (9).

SummaryNot only can sugar cause sleep issues in the short term, regular high sugar consumption can impact insulin resistance and lead to long term sleep trouble.

Sugar and Insomnia Create a Vicious Cycle

One thing we still don’t really know is whether sugar causes insomnia, or insomnia causes you to eat more sugar (10).

When you’re sleep deprived, you’re more likely to look for that quick boost of energy, and food that’s convenient (who’s going to cook when tired?).

All roads point to sugar in that case.

SummarySugar consumption can lead to poor sleep, which can then lead to more sugar consumption, creating a feedback loop that is hard to break and terrible for your health.

Sugar Makes You Hungrier

I’m sure you’ve noticed that when you eat something with a lot of sugar in it, it doesn’t really fill you up.

It’s really easy to eat 2,000 calories worth of cookies compared to the same amount of vegetables or beans.

Refined sugar increases a hormone called ghrelin (hunger-promoting), while decreasing levels of appetite-suppressing hormones (11).

SummarySo if you’re eating a lot of sugar, you’re more likely to overeat, which can cause discomfort, which then causes sleep issues. Or, you’re more tempted to eat at night shortly before sleeping, which is known to cause sleep issues.

High Sugar Consumption Can Lead to Weight Gain

For many reasons, eating a lot of sugar leads to gaining weight.

That’s not a problem up to a certain point, but obesity is one of the biggest insomnia risk factors.

One study showed that obese subjects were 38.5% more likely to develop insomnia (12).

Summary: How Sugar Consumption Affects Insomnia

A small amount of sugar per day is unlikely to cause significant sleep issues.

Some people even sleep better after some sugar.

However, regular moderate-high consumption of sugar is clearly linked to poor sleep quality. Like everything, it affects some more than others.

The exact mechanism of why sugar can be disruptive to sleep is not known right now, but research is starting to show it’s likely several smaller things that can contribute in different ways.

This includes:

  • Sugar increasing inflammation
  • Sugar depleting magnesium
  • Insulin resistance
  • Making you overeat
  • Leading to weight gain, which can lead to insomnia

While it's not common, sugar also triggers acid reflux (GERD) in some people. Research shows that acid reflux can cause insomnia.


  1. Relationship Between Added Sugar Intake and Sleep Quality Among University Students: A Cross-sectional Study
  2. Sleep duration and consumption of sugar-sweetened beverages and energy drinks among adolescents
  3. Fiber and Saturated Fat Are Associated with Sleep Arousals and Slow Wave Sleep
  4. Short and sweet: Associations between self-reported sleep duration and sugar-sweetened beverage consumption among adults in the United States
  5. Low to moderate sugar-sweetened beverage consumption impairs glucose and lipid metabolism and promotes inflammation in healthy young men: a randomized controlled trial
  6. Sleep and Inflammation
  7. The effect of magnesium supplementation on primary insomnia in elderly: A double-blind placebo-controlled clinical trial
  8. Sleep disturbances and insulin resistance
  9. Insomnia With Objective Short Sleep Duration Is Associated With Type 2 Diabetes
  10. Sleep extension is a feasible lifestyle intervention in free-living adults who are habitually short sleepers
  11. Effects of High-Fructose Diets on Central Appetite Signaling and Cognitive Function
  12. Risk Factors for Incident Chronic Insomnia: A General Population Prospective Study

Medical Disclaimer: The information on is not intended to be a substitute for physician or other qualified care. We simply aim to inform people struggling with sleep issues about the nature of their condition and/or prescribed treatment.

About the authorDale is the founder of Snooze University and a sleep researcher. I overcame my sleep issues and now I'd like to help you do the same by summarizing the latest sleep studies for you.