nutrition

Why Does Sugar Make Me Sleepy? The Science Made Simple

Dr. Carla Montrond Correia ND, CNS

Medically Reviewed by

Dr. Carla Montrond Correia ND, CNS

5 min read

a brown cookie with powdered sugar on top outlining the shape of a heart

If you’ve ever felt tired after eating sugar, you know that sugar affects your energy levels. Let’s review how and why this happens and what to do about it.

If you’ve ever felt tired after eating sugar, you know that sugar can affect your energy levels. And there’s a large base of research to show this. In this article, we’ll discuss why sugar can make you tired, as well as its effects on appetite, and what you can do to sustain your energy levels.

What happens in your body when you eat sugar

The body is naturally equipped for using sugar as an energy source. Sugars are naturally found in foods like fruit, milk, and a small amount is found in vegetables. Carbohydrates are foods that consist of sugars, starches, and fibers. In the body, both sugars and starches break down and become glucose which is the body’s primary energy source, whereas fibers are partially digested further in the gut by gut bacteria. Some sugar in moderation is acceptable in the body while still maintaining good health.

The sugar addiction cycle

One of the problems with consuming too much sugar is the sugar addiction cycle that can result. When eating highly palatable foods that are rich in sugar, especially with fat in combination, dopamine and naturally occurring opioids are released in the body and increase the desire for eating more of these foods. With these molecules around, the brain associates sugar as a reward. These neurochemical and behavioral changes can lead to dependency.

Why does sugar make me feel sleepy?

When consuming large amounts of sugar regularly, you may notice that you feel sleepy more often. Let’s review why that is.

Consuming too much sugar

The American Heart Association%20for%20most%20men. "American Heart Association") recommends less than 100-150 calories per day from added sugar daily or 6-9 tsp/day for women and men. That’s about 24-36 g of added sugar per day. Consuming high amounts of added sugar is known to increase the risk for health issues. It negatively impacts metabolism, weight management, and even gut flora.

Sugar and its effect on sleep

Regular excess sugar intake is known to negatively affect sleep. In a study of children, higher sugar intake was correlated with shorter sleep duration. Poor sleep quality is also associated with higher added sugar intake. Blood sugar levels throughout the day greatly impact your cortisol production over the course of the day, which can affect your sleep. In particular, high blood sugar levels, especially before bed, can make it harder to fall asleep and stay asleep.

Sugar and its effect on your orexin system

Orexin. "Orexin") is a hormone produced by neurons in the brain and has functions involving regulation of whole-body energy metabolism. In particular, orexin helps regulate sleep/wake stability, feeding behavior, emotions, and autonomic nerve activity. In addition, emerging evidence. "emerging evidence") indicates that sugar intake decreases the activity of orexin. Orexin activity is stimulated by dietary amino acids, compounds that make up proteins that actually prevent the block on orexin by glucose. Inactivation of orexin can promote overeating as well as feelings of tiredness.

Blood sugar spikes and crashes

Blood sugar spikes and crashes can lead to energy highs and lows. When blood sugar begins to rise in response to carbohydrate intake, the insulin hormone is released to allow the sugar in the bloodstream to enter the cells of our body to be utilized for energy or stored for later use. Simple carbs like sugars and refined flours can lead to spikes in blood sugar and insulin levels, which can often lead to blood sugar crashes. A crash in blood sugar often results in increased cravings for sugar and refined carbs as well as lower energy levels. This can lead to a vicious cycle, leaving people with growing sugar cravings, excess weight, and low energy.

Blood sugar control

By using food combinations and other nutrients, we can control our blood sugar. Combining protein with foods that have added sugars can help to stabilize sugar response in the body. Eating protein and vegetables at a meal before eating carbohydrates can significantly help lower post-meal blood sugar levels. Incorporating foods containing fiber at meals can also promote blood sugar control.

Why do sugar-free energy drinks make me sleepy?

Drinking sugar-free energy drinks regularly may lead to sleepiness due to the effects of chronic caffeine consumption. In one respect, frequent caffeine intake can negatively impact sleep, making you feel sleepy the next day. This can lead to a cycle of drinking more caffeinated drinks that further disrupt sleep, leading to more sleepiness over time.

How to prevent energy crashes and have sustained energy levels

Luckily, energy crashes can be prevented through simple dietary and lifestyle changes.

Avoid processed foods

Eating processed foods that are usually not nutrient-dense and low in fiber can lead to nutrient depletion and blood sugar imbalances. Such foods have also been shown to promote excess energy intake, leading to weight gain and metabolic issues that can lead to sleep disturbances. Instead, you can choose real, minimally processed foods as the mainstay of your diet.

Avoid eating sugary foods

Eating foods high in added sugar and refined carbohydrates can cause spikes in energy followed by energy crashes, since energy levels tend to follow blood sugar levels. Opt for naturally sweet whole food (like fruits) in moderation and as part of balanced meals.

Having healthy sleeping habits

Better sleep, consistent sleep schedule and getting between 7-9 hours nightly can be supportive of energy levels. Getting enough nutrients like calcium, magnesium, and vitamin D may also support sleep quality.

Incorporating protein and healthy fats into your diet

Combining carbs with protein and healthy fats results in higher energy levels through supporting blood sugar balance, showing the importance of food combining carbs rather than having carbs on their own.

Exercise regularly

Exercise is an effective tool for fatigue management, particularly resistance or strength training. One study showed that moderate intensity exercise training for at least 6 weeks is on average beneficial for fatigue, energy, and vitality in healthy individuals.

Having balanced electrolytes

Lack of balanced electrolytes may present as fatigue. You can ensure adequate electrolyte intake throughout the day by eating whole and minimally processed foods and adequately salting your food as well as using supplements.

Final takeaways

Excess sugar intake can make you feel sleepy for many different reasons, including its negative effects on blood sugar levels and sleep quality. With adjustments in diet and lifestyle, better energy levels are possible.

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