Blog Nutrition Sugar Makes Me Sleepy – Why Does This Happen And What Can I Do About It?

Sugar Makes Me Sleepy – Why Does This Happen And What Can I Do About It?

We’ve all experienced it before – you ate a few more slices of cake than you should and now you feel like you’re going to fall asleep at any moment. When this happens, most people write it off as regular exhaustion. However, there is more to this phenomenon than meets the eye. 

If you’ve been wondering “why do I get tired after I eat?” or “is it normal that sugar makes me fall asleep?” then we have all the answers to your questions in this article. 

What Happens in Your Body When You Eat Sugar?

When you eat a lot of sugar, your blood sugar level shoots up. This is a normal response to the sugar you have eaten. After all, food that has easily absorbable carbohydrates (e.g. table sugar or candy) causes rapid glucose absorption by active transport (7). 

Glucose enters the bloodstream and triggers insulin release from the pancreas. The insulin in your bloodstream helps get that glucose from your blood into cells so it can be used by them as a source of fuel. Eventually, after you eat a meal, your blood glucose levels will come back down again. 

Over time, various factors can cause the body to experience insulin resistance, which is where your cells become less sensitive to insulin, so they can’t transport that glucose from your bloodstream into your cells to be used as energy as easily as before. People with insulin resistance or diabetes may need to limit their sugar intake. Eating a diet that is high in sugar doesn’t directly cause diabetes, but it can contribute to weight gain and obesity, which can increase the risk of developing type 2 diabetes over time (1).

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Eating Sugar Makes Me Sleepy – Reasons Why This Happens

Too much sugar can also leave you feeling sleepy or fatigued (9). Here are the two main reasons why this could be happening to you:

Sugar and Your Orexin System 

The orexin system is made up of a pair of neurons that are found in the brain’s hypothalamus region. Both of these neurons, dubbed by researchers as OX1R and OX2R, act to stimulate the production of a chemical called hypocretin. This chemical stimulates wakefulness and brain activity, in addition to regulating your eating habits.  

When you eat sugar (which is broken down into glucose in the body), your blood sugar levels rise, which suppresses orexin release and leads to reduced activity of this system.

When your orexin levels are low, this makes you feel tired. When they’re high, you’re more energetic and awake. People with chronically low orexin levels often suffer from narcolepsy or obesity, as the chemical also influences metabolism (8). 

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Blood Sugar Spikes

The fatigue you feel soon after eating may be caused by a blood sugar spike, which is known as post-meal hyperglycemia. This is not uncommon and typically not dangerous. The levels should normalize after an hour or two (7). 

It is not always easy to determine whether you’re experiencing post-meal hyperglycemia. Many factors will influence your blood sugar levels after eating, such as the type of food consumed, the amount of food eaten, and your eating habits. 

You should pay special attention to how you feel if you’re pregnant or trying to get pregnant, as women with gestational diabetes and uncontrolled blood sugar are at risk of complications. If you’re diabetic, it’s also important to monitor how you feel (7). 

If you suspect high blood sugar is playing a part in fatigue during or immediately after eating, you should check your glucose level before you eat breakfast one day. 

For accurate results, take your glucose level first thing in the morning when you wake up and before you eat or drink anything. Then, you can eat your typical breakfast and check your blood sugar level an hour or two later to see if you have a prolonged or unusually high spike in glucose levels. 

You should talk to your doctor about the readings. In addition, consult a medical professional for additional advice on how to control high blood sugar.

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sugar makes me sleepy  

Eating Too Much Sugar Makes Me Sleepy, How Do I Avoid This?

There are several things you can do to avoid post-meal fatigue:

Avoid Eating Sugary Foods

If eating sugary foods makes you feel tired, then perhaps giving up those treats is best for you. There are plenty of healthy snacks out there that will keep you satisfied without sabotaging your energy levels. 

If your sweet tooth makes treats too difficult to resist, plan your meals for the day and try to include no more than one serving of a sweet treat (this is approximately 200 calories). 

Or eat a piece of fruit, which will give you that sweet taste of sugar in addition to the fiber that slows down the absorption of sugar into your bloodstream.

Eat Frequently But in Smaller Portions

Eat your meals spaced 1-2 hours apart rather than eating too much at once. 

If you eat a lot in one sitting, you should make sure it’s not right before bedtime as this may result in post-meal fatigue and grogginess the following day. This way, you’ll give your body enough energy without becoming too tired after any one meal.

Never Consume Alcohol on an Empty Stomach

Drinking alcohol before you eat is known to disrupt blood sugar balance and may leave you feeling drowsy as a result (3). If you intend to drink alcohol, never do it on an empty stomach. Try eating a healthy meal that contains some protein beforehand.

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Read more: Keto and Sugar: Can You Have Them Both?


Exercise helps with blood circulation and can stimulate the sympathetic nervous system to increase energy levels (5). This can be anything from a simple walk to a full-on gym session. In addition, being active can help you maintain a healthy weight. 

Balance Electrolytes

Take in enough electrolytes as the body needs them to maintain normal fluid balance for proper cellular function (4). Dehydration can also cause fatigue.

Using a little salt or eating high-sodium foods like almonds and avocados is helpful for this purpose. Don’t forget to drink water too. Drinking a natural sports drink with extra sodium may also help keep you awake after eating sugar.  

Practice Healthy Sleep Habits

Your daytime drowsiness may be worsened by poor nighttime sleep.  Make sure to:

  • Sleep in a dark room. Use heavy, lined curtains and block out as much light as possible. Get blackout curtains if necessary.
  • Avoid using electronic devices before bed, as even the tiny amount of light from a phone or alarm clock can delay your circadian rhythm (2). The best way to make sure this happens is to put your device on airplane mode before sleep. 
  • Limit eating at night. Eating too close to bedtime activates the digestive system, which is likely to be what’s keeping you up later than usual anyway. Avoid eating after 7 PM if possible and be aware of how your body feels after you eat late at night.  
  • Exercise regularly, but not too close to bedtime (2 hours or so at least). Exercise helps burn off sugar throughout the day and has also been proven to improve sleep quality  (6). 
  • Avoid caffeine after 2 PM if possible. Caffeine can remain in your system longer than you might think and being awake when it wears off can lead to grogginess. 
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sugar makes me sleepy  


  • How do you stop sugar tiredness?

One approach could be to adjust your diet to include foods with a lower glycemic index that release sugar more slowly into your bloodstream. This will help avoid sudden spikes and crashes in energy levels. This may mean replacing refined types of sugar with more natural alternatives, such as whole fruits that include fiber and water.

Physical activity, particularly after a meal, can also help. Engaging in a light workout after consuming sugar aids digestion and also helps regulate blood sugar levels, which prevents precipitous drops in energy (10).

Our blog, Sugar After Workout, goes into more detail about the relationship between sugar and exercise and provides tips on when and how much sugar to consume before a workout.

You could also consider a no-sugar diet, which involves avoiding foods that are high in added sugars. However, it should be noted that this doesn’t mean you need to exclude sugar entirely from your diet, as certain types of natural sugars that are found in fruits and vegetables are essential for energy production in the body.

Finally, understanding your body’s response to different types of sugar can help with the management of your energy levels and prevent sugar-induced tiredness.

  • How long does sugar fatigue last?

Sugar fatigue can last anything from 30 minutes to a few hours. It starts to kick in approximately 30 minutes after consuming sugar and can last for up to 2 hours. However, if you have an undiagnosed underlying health condition such as insulin resistance or diabetes, your experience may differ.

If you often experience post-sugar fatigue or it lasts longer than a few hours, it’s best to talk with your doctor to rule out any potential underlying medical issues. 

In the meantime, you can try implementing some of the tips mentioned above to help manage your energy levels after you consume sugar.

  • Can I sleep 30 minutes after eating?

It is generally recommended to wait 2-3 hours after eating before you go to sleep. This allows for proper digestion and prevents discomfort or other issues that may arise from sleeping immediately after a meal, such as heartburn or reflux.

However, if you feel extremely drowsy or fatigued on occasion after consuming sugar, it’s okay to take a short nap of approximately 30 minutes. Just make sure you set an alarm and wake up on time to avoid disrupting your nighttime sleep schedule.

  • Is it better to go to bed hungry or full?

Neither. Going to bed too hungry or too full can disturb your sleep and affect your energy levels the following day.

If you go to bed incredibly hungry, your body may release cortisol (the stress hormone) in response, which can disrupt your sleep cycle and lead to poor-quality sleep. 

At the same time, going to bed when you’re too full can cause discomfort and indigestion, which will make it difficult to fall asleep and stay asleep.

You should aim for a light snack or small meal at least 2-3 hours before bedtime to avoid these issues. If you constantly feel extremely hungry or full before bed, it may be worth reevaluating your eating habits and adjusting them accordingly. 

In addition, practicing good sleep hygiene can also help improve the quality of your sleep.

The Bottom Line

Eating sugar reduces the activity of your orexin system, which is partially responsible for the regulation of your sleep and wake cycles. This is why foods such as cake or candy can reduce your alertness and cause you to feel groggy. 

To prevent this, you should keep your daily sugar intake within the recommended range and eat an overall balanced diet. You should also try to avoid eating lots of sugary foods at once as this can lead to a surge in blood sugar levels that may potentially result in hyperglycemia symptoms.


This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!


  1. A review of recent evidence relating to sugars, insulin resistance and diabetes (2016,
  2. Blue light has a dark side (2020,
  3. Consequences of Alcohol Use in Diabetics (1998,
  4. Electrolytes (2023,
  5. Exercise and the autonomic nervous system (2013,
  6. Here’s Why You Get Sleepy After Eating (2023,
  7. Hyperglycemia (2021,
  8. Sleep disorders, obesity, and aging: the role of orexin (2014,
  9. Tired after eating? Here’s why, and how to fix it (2023,
  10. Why Do I Get Tired After Eating? (2023,
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