Sugar Insomnia: The Effects of Sugar Before Bedtime

Learn why sugar may be the cause of your nighttime insomnia.

By Andrea Pisani Babich

Apr 20th, 2022

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Here’s good news for people who suffer from insomnia: if you toss and turn trying in vain to fall asleep, or if you wake in the middle of the night and can’t get back to sleep, it may be your diet that’s to blame.

Sugar is a huge part of American’s diets. Between candy, soda, and even foods like pizza, we consume a lot of sugar every day. You may not realize it, but this can affect your sleep in a harmful way.

Which Sugary Foods Disrupt Sleep?

According to an analysis of data collected by the Women’s Health Initiative Observational Study between 1994 and 2001, women who ate foods with high refined sugar content had an increased incidence of insomnia compared to women whose diets were higher in fruits and vegetables and lower in added sugars.

Researchers extrapolate from this finding that you may be able to get the sleep you need simply by reducing your intake of processed foods with high levels of added sugar. These include the obvious foods like cake, cookies, ice cream, soda, and sports drinks. It also includes less-obvious suspects like yogurt, breakfast cereals, jarred spaghetti sauce, canned soup, frozen meals, salad dressings, and ketchup to name a few.

For some people, cutting down on their sugar intake is a much better solution than current conventional insomnia treatments. While insomnia can be treated with cognitive behavioral therapy and/or sleep medications, these can be costly and carry side effects that discourage compliance. But everyone can reduce the amount of added sugars they consume as a simple and cost-free way to help them get the rest they need.

How Does Sugar Cause Insomnia?

The original observational study collected baseline data from 77,860 postmenopausal women and then from 55,069 of those women three years later. Among the data were dietary measures of the women’s

  • overall glycemic index (GI), which measures how much foods raise blood sugar levels after eating
  • glycemic load, which combines the type of carbohydrates in foods plus the quantity eaten
  • consumption of specific types of carbohydrates such as refined sugars and starch
  • consumption of whole grains, refined grains, fruits, vegetables, and dairy products

Other data tracked how often and for how long participants suffered sleep disruptions.

James Gangwisch, Ph.D., senior author of the new study, and his team found a high correlation between diets high in added sugars and sleep loss due to insomnia. They also found that women who ate more dietary fiber, whole grains, whole fruits and vegetables faced significantly lower risks of insomnia. “This suggests that the dietary culprit triggering the women’s insomnia was the highly processed foods that contain larger amounts of refined sugars that aren’t found naturally in food.”

Gangwisch notes that his team’s analysis does not prove causation. It was not clear from their study whether the consumption of carbohydrates caused insomnia or if people who suffered sleep disruptions were more inclined to eat refined carbs and sugary foods. Either could be the case or a combination of causes could explain participants’ insomnia.

A recent study published in the journal Sleep not only confirmed that people who experience insomnia crave high carb, sugary food but also indicated that sleep deprivation results in  hormonal changes that lead to those cravings. In Gangwisch’s study, it may have been the women’s insomnia that led them to eat a lot of foods with added sugar.

However, there is also a physiological mechanism that explains how a diet high in added sugar could lead to insomnia. Gangwisch explains, “When blood sugar is raised quickly, your body reacts by releasing insulin, and the resulting drop in blood sugar can lead to the release of hormones such as adrenaline and cortisol, which can interfere with sleep,” Gangwisch explains.

Gangwisch acknowledges that more research is needed to conclusively determine the causal relationship between sugar consumption and insomnia. He hopes to conduct randomized clinical trials to help determine if simple dietary changes to limit refined sugars and increase consumption of whole foods and complex carbohydrates can empower patients to prevent and treat insomnia on their own.


While there is still more research needed to fully understand the correlation between sugar intake and insomnia, it is clear that cutting refined sugars from your diet can be a good start to solving your insomnia issues. Just like we know that it’s wise to avoid excessive alcohol or caffeine before bedtime, we should also be monitoring our sugar intake before bedtime and also during the day.

Not only will this be better for your nutrition, but it can also benefit your sleep.