Why Does Sugar Make You Feel So Sleepy?

You may have thought this to yourself. Or even said these words out loud: sugar makes me sleepy. Maybe it just makes you feel tired. But why do you feel tired after eating sugar? Not many people actually know the answer to this. Although “it’s complicated,” I’m going to put it in simple terms so you better understand it. After all, knowing is half the battle.

Sugar rush
Sugar rush is a term that gets thrown around quite a bit. It’s an old saying that refers to the high you feel after consuming sugar. It usually manifests as increased energy and happiness. Despite people’s assumptions that this is a real thing, research suggests otherwise. A meta-analysis (which looked at 31 different studies) found that the opposite is true. If there’s no such thing as a sugar rush, then how can so many people be wrong about it? Surely you’ve seen kids at parties running around and acting like miniature maniacs after consuming sweets.

Cognitive bias
The answer to this question may have more to do with expectation than anything else. Expectations cause cognitive biases, which clouds judgment. According to Wikipedia, cognitive biases are a “…systematic pattern of deviation from norm or rationality in judgment. Individuals create their own ‘subjective reality’ from their perception of the input.” In short, you see what you want to see. If you think about kids at the parties above, if they’re more hyper, then other reasons may be to blame. They are likely having more interactions than they usually do and are energized by them rather than the sugar they’re eating. 

Sugar consumption is related to a decrease in alertness and higher levels of fatigue. And these occur within an hour of eating sugar, or an excess amount of carbohydrates. That sounds more like a sugar crash if you ask me. But why does that happen instead of the infamous sugar rush?

Sugar crash
A sugar crash is technically called hypoglycemia. It occurs when your blood sugar gets too low. What happens is that your body has more sugar than it’s accustomed to. This causes it to rapidly produce insulin to help keep blood sugar levels consistent. As a result, blood sugar levels decrease and cause a drop in energy levels. 

Hypoglycemia isn’t something that only happens to diabetics. A sugar crash that occurs within 4 hours of eating is called reactive hypoglycemia. The exact cause of this isn’t known. Many experts believe that it’s related to not only the foods you eat, but the time it takes to digest them. Making some adjustments to your diet can still be helpful. 

It’s rare to have reactive hypoglycemia (aka sugar crash) without being diabetic, or at least having prediabetes. In short, all cases of hypoglycemia are because of low blood sugar levels (glucose) in your body. Glucose can be obtained from foods you eat, not only sugar itself. For example, you can get it from any source of carbohydrates. This includes: fruits, vegetables, and grains. Glucose is the fuel that your body needs to power itself. In fact, it’s your body’s main source of energy. Your brain also needs glucose, which is why you might feel weak and irritable during a sugar crash. 

If you’re not sure what your blood sugar levels are, talk to your doctor about getting them tested. You can learn all about the different tests in a blog post I wrote entitled: Better Understanding Your Blood Sugar Results. Once you know what your blood sugar levels are, you can take action to correct them if needed. 

How to avoid a sugar crash
Let’s face it, nobody wants to have a sugar crash. They generally leave us feeling distracted, which leads to compromised productivity, as well as difficulties concentrating. Fortunately, there are simple steps we can take to avoid a sugar crash altogether. The key is to incorporate balance by keeping blood sugar levels as consistent as possible. 

  • Eat a variety of foods. That is, try to balance your major food groups and nutrients. Strive for incorporating protein, carbohydrates, fat (the 3 macronutrients), and fiber into meals and snacks. 
  • If you consume simple sugars (deserts, fruit juice, candy), then either eat them with a meal consisting of all 3 macronutrients, or have them after a meal
  • Eat more often, but eat less. Try snacking between meals, eating smaller portions throughout the day. Although I’m not a big proponent of counting calories, your caloric intake shouldn’t change throughout the day. Think about it like a pizza pie: you can cut it into 8 slices, or 48 if you’d like. Either way, you’re consuming the same amount of pizza.
  • Don’t restrict any foods or food groups. Unless you have dietary restrictions or food sensitivities or allergies, enjoy your food but don’t overdo it with any one food, food group, or macronutrient
  • Plan ahead: do your best to ensure that your meals have a good balance of proteins, carbohydrates, protein, fat and fiber. This might mean meal planning or looking ahead at menus when eating out. 

In case of emergency
If you’re experiencing a sugar crash and trying to get out of it, you might think that some quick sugar might help. After all, many foods claim to help increase your energy levels, but not all will deliver. It might temporarily give you a boost, but your sugar crash will be inevitable. As a general rule, don’t go for carby or sugary foods at times like these. When you’re having a sugar crash, your body is looking for protein to help balance your glucose. A protein bar might be useful in cases like these, but check the sugar content. The net carbs should be on the lower side. Otherwise, consider foods like nuts, cheese, meat, etc. 

What about sleep though?
If sugar can make you feel tired, then it seems logical that it can help you fall asleep. Once again, it’s not what you think. According to a study on added sugar intake among college students, poor sleep quality is related to the higher intake of added sugar. 83% of participants reported poor sleep quality. This was the 1st study to directly speak to the effects of a higher intake of added sugars on the quality of sleep. Another study found that those with diets high in sugar don’t sleep as deeply and they are more restless at night. In fact, some of these foods even contain caffeine. For instance, caffeine can be found in foods like: chocolate, ice cream, protein bars, decaffeinated coffee (much less than in regular coffee, but those more sensitive to caffeine could still have their sleep compromised), cereal, and even headache medications. Sugar uses up a significant amount of magnesium, something we need for sleep. This is why some people supplement on magnesium, although you shouldn’t think of it as a license to eat more sugar. Eating too much sugar also leads people to eat later in the day because blood sugar levels are out of control. Not only does this impact sleep, but it plants the seed for a bigger sugar craving the next day. How’s that for a vicious cycle? 

What are your strategies for avoiding a sugar crash? Please tell us in the comments below…