6 Reasons Why You Feel Sleepy After Eating Sugar

You may have heard about that energy crash you get after eating a high-sugar food. 

However, if this frequently happens, you may be concerned if it’s a sign of something more serious, such as diabetes. 

While feeling sleepy after eating something with sugar is not an indicator of diabetes, it is an important symptom you need to be on the lookout for. 

Several factors can indicate why you are having an energy slump after eating. 

The types of foods you eat and the time can all affect you. 

In this article, we’ll dig into the link between feeling sleepy or sluggish after eating sugar and the relationship between diabetes. 

Is Falling Asleep After Eating Sugar A Sign of Diabetes?

It depends on how often this occurs. Falling asleep after eating sugar every now and then is not a sign of diabetes.

But, if it happens frequently and despite changing your nutrition, you still feel sleepy after eating, it can be a good idea to ask a health professional to get blood work. 

Falling asleep after eating may indicate changes in your sugar levels. When you eat, the body signals the pancreas to release insulin to allow sugars to enter the body’s cells. 

When the body cannot produce good insulin (or not enough), it can lead to sugar buildup in the bloodstream (high sugar levels). 

If you have diabetes, high sugar levels (hyperglycemia) or low sugar levels (hypoglycemia) can make you feel short on energy, resulting in drowsiness. 

However, other factors besides diabetes may affect your energy levels. 

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Other Causes of Feeling Tired After Eating

1) How Much You Eat

I know that most of us have experienced feeling drowsy after having a big meal. 

While there are not a lot of studies regarding this topic, it seems that eating too much can pause every process for your digestive system to work on the heavy food load. 

But eating too much is not the only way you can feel sleepy. Eating too little can also make you feel tired after a meal. 

When you don’t give your body the necessary calories to function, it can drain your energy, making you feel tired throughout the day

2) The Foods You Eat 

Foods high in protein and carbs can lead to sleepiness throughout the day. 

High-protein foods, like turkey or chicken, contain tryptophan, an amino acid transformed into serotonin (a neurotransmitter that research shows regulates sleep). 

That is why you most likely feel like taking a post-dinner nap after a big turkey meal at Thanksgiving. 

Another food that can cause you to feel sleepy is simple carbs. Even if you don’t have diabetes, simple carbs raise your sugar levels very quickly, producing an energy rush. 

But, since the body works hard to create stable blood sugar levels, it produces an energy crash. 

So, eating sugary foods like sodas, ice cream, candy, and sweets may be the culprits of your recurrent naps. 

3) How Much You’re Exercising

In some people, a workout session can boost their energy, while in others, it can do the opposite. 

4) How Much Sleep You’re Getting

Getting good quality sleep and focusing on recovery can also affect whether you feel tired after eating. 

When you have a poor night’s sleep, the body may feel more tired throughout the day. Also, it craves more simple carbs to get fast energy, producing a vicious cycle of energy rush and crash. 

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5) Certain Medical Conditions 

On rare occasions, there may be other underlying conditions that may make you feel sleepy after eating sugar. 

Some conditions that may make you drowsy after a meal include: 

  • Anemia
  • Celiac disease
  • Food intolerances
  • Sleep apnea

If you have one of these conditions or think you may have one, talk with a healthcare provider to get an adequate diagnosis. 


Experiencing fatigue after meals may warrant attention, and it could be associated with various factors, including blood sugar levels.

Unstable blood sugar levels can have a huge role in your energy levels. 

However, don’t panic right away. Other factors may affect your energy levels after a meal, such as the quantity and types of foods eaten, sleep, and activity levels throughout the day. 

If you consistently feel fatigued after eating, it’s advisable to seek advice from a healthcare professional to explore potential causes.

Explore More

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Diabetes Fatigue: Causes and Management.


  1. Sutanto CN, Loh WW, Kim JE. The impact of tryptophan supplementation on sleep quality: a systematic review, meta-analysis, and meta-regression. Nutr Rev. 2022 Jan 10;80(2):306-316. doi: 10.1093/nutrit/nuab027. PMID: 33942088.
  2. WaterhouseJ, et al. (2007). The role of a short post-lunch nap in improving cognitive,motor, and sprint performance in participants with partial sleep deprivation [Abstract].

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