Sleep and Glucose: Can Sugar Disturb Your Sleep?

Can too much sugar in diet cause sleep disturbances? | Photo by Lukas on

A lot of the things we consume contain sugar in them; be it your takeouts, fast food, energy drinks, juices— you name it. The average sugar intake in current times has gone up significantly when compared to earlier. Either sugar is added to these foods and drinks, or most of these ‘good to taste’ foods are made up of simple carbohydrates that are very quickly broken down in our body into glucose. In either case, there is a spike of glucose in our bloodstream soon after consumption.

Now, it’s no news that we consume a lot of sugar. We are also slowly finding out more and more about the consequences of consuming a lot of sugar. But is sleep disturbance one of them?

Can too much sugar intake disturb your sleep? 

Sugar (or glucose) can affect your sleep negatively. Although, as per studies simple sugar (or high glycemic index foods) might initially help you fall asleep quickly as it inhibits a substance called orexin— a chemical that keeps us awake and alert. However, studies also say that the sleep we get after consuming sugary food and drinks is of poor quality. So, your sleep after sugary drinks and foods is not going to be as restorative as it should be.

Sugar, like caffeine, is indeed one of those substances that you should avoid before bedtime, as it can disturb your sleep when taken close to bedtime. This is especially important if you are someone who struggles to get good quality sleep most nights.

For people who struggle with getting good quality sleep, some simple nighttime routines and sleep hygiene practices can help improve sleep patterns to a great extent, and what they eat and drink before bedtime is one major factor to consider. 

Also note that, when it is said sugar disturbs sleep, we are referring the refined sugar, and not the sugar that comes out of food, like complex carbohydrates and fruits— as they don’t cause a sudden spike in blood sugar levels. 

Simple carbohydrates in the form of food should be a part of your diet as well but in moderation and in combination with complex carbohydrates. Carbohydrates are not the villain!

What Do The Studies Say About Sleep and Blood Sugar Levels?

Now, normally, during sleep, blood sugar is naturally elevated in everyone (and not just in diabetics). This is not an abnormal phenomenon, and this doesn’t cause disturbance in sleep and is not a matter of concern. 

Here we are referring to the excessive consumption of refined sugar and its effect on sleep, and vice-versa.

1. Consuming too much sugar before bedtime disrupts your sleep cycle and leads to poor sleep at night, as that can stimulate your system.

2. Studies also say that people who, in general, consume a lot of refined sugar throughout the day experience poor quality of sleep. Such individuals also experience difficulty in falling asleep and more nighttime awakenings when compared to people who don’t consume too much sugar during the daytime. They also spend less time in the deep sleep state— which is the restorative phase of sleep. As a result, you wake up not feeling very refreshed.

3. When you consume too much sugar during the day, or when you consume too much sugar before bed— your sleep is disturbed. This results in poor quality of sleep.

Now, poor quality of sleep is associated with elevated levels of the hunger hormone (ghrelin) and reduced levels of the satiety hormone (leptin). This translates to overeating during the day due to lack of sleep. A lack of sleep also results in increased sweet cravings. So, it’s a vicious cycle— too much sugar leads to poor sleep and poor sleep results in sweet cravings.

4. Too much sugar further increases cravings for sugar. This is because when you consume too much refined sugar, your body releases an increased amount of insulin than usual to deal with elevated blood sugar levels.

The insulin brings down the blood sugar levels— causing a sudden drop in blood sugar levels— which then triggers sugar cravings, as you need glucose in your system for energy.

5. Emotional eating or habitual consumption of too much sugar also blunts your reward system a bit. Normally, when you consume sugar, it triggers your reward system in the brain and causes the release of dopamine—- which makes you feel good.

But when you consume too much sugar, eventually your reward system stop responding to the sugar intake, and you don’t get the same good feeling you were previously getting as a result of sugar intake. At this point, your reward system requires more sugar intake to get the same kind of response for the release of dopamine.

Basically, you develop a certain degree of tolerance towards sugar, and you consume more sugar to get the same response as you did earlier with less amount of sugar. 

So, as you see, all of it triggers the kind of cycle that promotes more sugar consumption, and as a result, all of it will affect your sleep.

The Recommended Amount Of Refined Sugar Consumption Per Day

In general, the recommendation for refined sugar is less than 10% of your total calorie intake. So, for a 2000-calorie diet, less than 200 calories should come from sugars. 

However, the American Heart Association suggests being a little more aggressive with sugar intake to prevent obesity and heart disease— considering how easy it is to overdo sugar in the present times and how poor our lifestyles have become.

The American Heart Association suggests:

  1. For adult women— less than 100 calories/day (6 teaspoons or 24 g) of refined sugar per day.
  2. For adult men— less than 150 calories/day (9 teaspoons or 30 g) of refined sugar per day.
  3. For 2-18 years— less than 6 teaspoons or 24 g per day of sugar, and sugary beverages with an 8-ounce per week limit for kids.

1 teaspoon = 4 gm of sugar.

Use this reference to calculate the total sugar in bottled beverages and other packaged/processed foods. You’ll be surprised!

When Should Be Your Last Sugary Drink/Food For A Good Quality Sleep?

Since sugar can disturb your sleep, it’s important that space your sugar-rich food and drinks well before your bedtime. 

Insulin takes about 2 hours to bring the blood sugar down after we have consumed anything sugary. So, for a plain sugary drink— like juices— your last glass of sugary drink should be at least 2 hours before bedtime. 

But, here’s the thing: many of the sugary drinks are also quite often full of caffeine— like in energy drinks and soft drinks. If your drink contains caffeine in addition to a lot of sugar, your last caffeinated drink should be at least 8 hours before your bedtime. You can read about why you need to space it that much here in this article: Caffeine and sleep: how sleep affects you.

Now, even though it takes insulin 2 hours to lower the blood sugar level, as per studies, when it comes to food, meals consumed within 3 hours of bedtime lead to poor sleep. 

So, the bottom line is, your last sugary drink should be at least 2 hours, food (in general) should be 3 hours, and caffeinated drinks should be at least 8 hours before your bedtime— to preserve your sleep quality.

How To Prevent Sleep Disturbance Due to Refined Sugar

1. Don’t consume sugar too close to bedtime. 

First things first, as explained in the above section— you need to properly space your sugary foods and drinks before bedtime. It’s going to be a different number for food, plain sugar-rich drinks and caffeinated sugar-rich drinks.

So, refer to the above sections to know how to space food and drinks before bedtime.

2. Prioritise sleep.

The second most important factor is sleep itself, especially if you crave sugar most days. A lack of good-quality sleep is associated with increased sugar cravings. Meaning, if your sleep quality is of poor quality, you are more likely to crave sugar.

So, sleeping well at night ensures that you don’t get sugar cravings. 

3. Learn to better manage blood sugar levels with better food choices. 

The issue with consuming too much refined sugar is that it promotes sugar cravings even more. This is because as soon as our blood sugar level increases, our body releases insulin and clears up the glucose from our circulation— causing a sudden drop in blood glucose levels, which triggers sugar cravings.

So, to tackle the sudden rise and drop in blood sugar levels, eat foods rich in complex carbohydrates, proteins and healthy fats.

The reason is, these food are digested slowly and so the sudden rise of blood sugar levels never happen with this food. You will have fewer cravings for sugar as you will have a constant supply of energy for a longer period of time. 

4. Avoid drinking or eating too much refined sugar. 

As mentioned above, consuming refined sugar causes a sudden spike in blood sugar levels, which then triggers the release of insulin— which lowers the blood sugar level rapidly. This whole process triggers sugar cravings.

The more refined sugar you consume, the more you will be craving sugar. If you limit your refined sugar intake overall, your sugar cravings will go down.

So, limit commercially produced sweetened fruit juices and concentrates, energy drinks, chips and other processed foods.

So, What Do You Need To Remember About Sleep And Blood Sugar Levels?

As we have seen, too much sugar consumption before bedtime or during the day can disturb your sleep quality. A high or fluctuating blood sugar level will promote more sugar cravings and will lead to poor quality of sleep.

The solution is to manage your blood sugar levels well with the help of better food choices and ensure you are practising good habits that promote good sleep. 

The recommended amount of healthy sleep for adults is 7-9 hours, and the recommended amount of sugar intake is 6 and 9 teaspoons per day for adult women and men, respectively.

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