We’ve all experienced it before – you had a few more slices of cake than you should and now you feel like you are 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 really sleepy?” 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 body becomes hyperglycemic. That is to say, your blood sugar level shoots up. This is a normal response to the sugar you ate. After all, food that has easily absorbed carbohydrates (e.g. table sugar or candy) causes rapid glucose absorption by active transport (5).
Glucose enters the bloodstream and triggers insulin release from the pancreas. The insulin in your bloodstream helps to get that glucose from your blood into cells so it can be used by them as a source of fuel. Eventually, after eating 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. That’s why having a diet high in sugar especially when combined with high fat foods can lead to obesity and type 2 diabetes (1).
Eating Sugar Makes Me Sleepy – Reasons Why This Happens
Too much sugar can also leave you feeling sleepy or fatigued. 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 found in the brain’s hypothalamus region. Both 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, as well as regulates our eating habits. When you eat sugar (which is broken down into glucose in the body), your blood sugar levels rise which in turn suppresses orexin release leading to reduced activity of this system.
When orexin levels are low, it makes you feel tired. Vice versa, when they’re high, you’re more energetic and awake. People with chronically low levels of orexin often suffer from narcolepsy or obesity, since the chemical influences metabolism too (6).
Blood Sugar Spikes
The fatigue you feel soon after eating may be caused by increased blood sugar. The spike in a person’s blood sugar after eating, known as post-meal hyperglycemia, is not uncommon and typically not dangerous. The levels should normalize after an hour or two (5).
It is not always easy to determine whether you are suffering from 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 the individual’s eating habits.
Pay special attention to how you feel if you’re pregnant or trying to get pregnant – women with uncontrolled blood sugar are at risk of miscarriage and birth defects. If you’re diabetic, it is also important that you monitor how you feel (5).
If you suspect high blood sugar is playing a part in fatigue during or immediately after eating, check your glucose level before eating breakfast one day. For accurate results, take your glucose level first thing in the morning when you wake up and before eating or drinking anything. Then, eat your typical breakfast and check your blood sugar level about an hour or two later to see if you have a prolonged or unusually high spike in glucose levels. Talk to your doctor about the readings. In addition, consult with a medical professional for additional advice on how to control high blood sugar.
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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 really makes you feel tired, then maybe giving up those treats is best for now! 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 hard to resist, plan out your meals for the day and try to include no more than one serving of a sweet treat (this is about 200 calories). Or have a piece of fruit, which will give you that sweet taste of sugar but along with fiber that slows down absorption of the sugar into your bloodstream.
Eat Frequently But In Smaller Portions
Eat your meals spaced 1-2 hours apart instead of eating too much at once. If you are eating a lot in one sitting then make sure it is not right before bedtime as this might result in post-meal fatigue and grogginess the next day. This way, you’ll give your body enough energy without getting too tired after any one meal.
Never Consume Alcohol On An Empty Stomach
Drinking alcohol before eating 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 so on an empty stomach! Try eating a healthy meal beforehand that contains some protein.
Exercise helps with blood circulation and can stimulate the sympathetic nervous system to increase energy levels (4). It can be anything from a simple walk to a full-on gym session. Plus, being active can help you maintain a healthy weight.
Take in enough electrolytes as the body needs them to maintain normal fluid water balance for proper cellular function. Using sea salt or eating high sodium foods like almonds and avocados is helpful for this purpose. Don’t forget to drink water as well! Drinking a natural sports drink with extra sodium can 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 not feasible.
- Avoid using electronic devices before bed, 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 bed.
- Limit eating at night. Eating too close to bedtime activates the digestive system, which is likely 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 eating 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 is shown to improve sleep quality as well!
- Avoid caffeine after 2 PM if possible, caffeine can last in your system longer than you’d think! And being awake when it wears off can induce grogginess.
The Bottom Line
Eating sugar reduces the activity of your orexin system which is partially responsible for regulating your sleep and wake cycles. It’s why foods such as cake or candy can reduce your alertness and cause you to feel groggy. To prevent this, keep your daily sugar intake within the recommended range. Also, try to avoid eating lots of sugary foods at once as it can lead to a surge in blood sugar levels that may result in hyperglycemia symptoms.
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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!
- A review of recent evidence relating to sugars, insulin resistance and diabetes (2016, nih.gov)
- Blue light has a dark side (2020, harvard.edu)
- Consequences of Alcohol Use in Diabetics (1998, nih.gov)
- Exercise and the autonomic nervous system (2013, pubmed.gov)
- Hyperglycemia (2021, nih.gov)
- Sleep disorders, obesity, and aging: the role of orexin (2014, nih.gov)