Feeling sleepy after eating as a sign of diabetes: Other causes and how to prevent sleepiness after eating

It's often normal to occasionally feel sleepy after eating as a result of stress, lack of adequate sleep, or the kind of food consumed. However, when this becomes frequent, it might be a sign of an underlying health condition like diabetes.

Image of a lady with afro hair sleeping on a wooden long chair under a coconut tree

Key takeaways

  • Feeling tired, weak, or sleepy after a meal may be normal on some occasions, and several factors may contribute to this, e.g., the composition of the food you consume or stress.
  • Regularly feeling like sleeping after eating, however, may be an early sign of diabetes, particularly when associated with other diabetes symptoms, such as frequent urination, thirst, and/or unexplained weight loss.
  • Getting a good night's sleep, consuming a diabetes-recommended diet, and staying hydrated are some ways people with diabetes can prevent the frequent feeling of tiredness and sleepiness after eating.

Feeling tired, weak, or sleepy after a meal, also referred to as postprandial somnolence or food coma, may result from a chain of events that occurs during food digestion and metabolism. 

Carbohydrates, proteins, and fats are the primary nutrients in foods. Once food is consumed, the body breaks it into its simple forms and ultimately converts them into glucose, an important source of fuel for the body cells. When this happens, glucose gets absorbed into the bloodstream and is transported to the cells.

The levels of glucose in the blood change throughout the day. It can rise after a meal and return to its initial level within 2 hours after eating.

Insulin (a hormone responsible for transporting glucose from the blood to the cells) is produced in response to high blood glucose levels. Once the glucose levels in the blood return to their initial levels, insulin production decreases. 

If the body produces little or no insulin to move the glucose into the cells, or if the cells stop responding normally to insulin, it results in constant high levels of glucose in the blood (hyperglycemia), which is the case in diabetes.

Also, when there's excessive production of insulin resulting in too much conversion of glucose, the blood glucose level drops (hypoglycemia). It can, however, be said that feeling tired or sleepy after eating may be linked to the hypo- or hyperglycemia experienced post-meal, particularly in people with diabetes.

Is falling asleep after eating a sign of diabetes?

Falling asleep after eating can be a sign of diabetes if it occurs often. When the constant feeling of falling asleep after eating occurs along with other signs and symptoms of diabetes, e.g., frequent urination, increased hunger and thirst, and unexplained weight loss, it can be a pointer that a person may have diabetes.

However, feeling sleepy after eating is not an exclusive sign of diabetes. Other health conditions, such as hypothyroidism and sleep disorders, may present with postprandial somnolence as one of the symptoms.

So, it's important you see a doctor for a proper health evaluation if you notice you've been regularly falling asleep or feeling tired after eating.

Why people with diabetes may feel sleepy after eating

Several factors may contribute to people with diabetes feeling sleepy after eating. However, the major factor involved is the change in blood sugar levels.

1. Hyperglycemia and the body doing more work to produce insulin after eating

In people with diabetes, there's either little to no insulin available to convert the blood glucose to energy for the cells to use, or the cells are resistant to the available ones, i.e., the cells do not respond to the available insulin.

This results in high blood glucose levels (hyperglycemia) while still depriving the cells of glucose and causing a drop in energy, which may lead to the feeling of tiredness or sleepiness in people with diabetes.

In response to hyperglycemia, the body does more work to produce more insulin in an attempt to reduce blood sugar levels. This may lead to a drop in energy levels, causing one to feel tired or sleepy after meals.

2. Hypoglycemia and blood sugar crash

Feeling sleepy after meals in people with diabetes may also be caused by hypoglycemia resulting from a ‘blood sugar crash'. A blood sugar crash is a sudden drop in sugar levels shortly after meals.

This occurs when you consume diets containing simple sugars, e.g., cakes, white bread, candies, and processed/ultra-processed foods. These diets are quickly digested and increase blood glucose levels, leading to a high production of insulin, which quickly crashes the blood glucose, resulting in a sudden drop in energy.

3. Diabetes medications

Also, hypoglycemia may result from diabetes drugs such as metformin (Glucophage) and glibenclamide. The primary goal of diabetes drugs is to reduce blood glucose levels by increasing the production of insulin or the sensitivity of the cells to the available insulin.

This activity may lead to an excessive reduction of the blood glucose level, which may result in low energy levels and subsequent feelings of tiredness or sleepiness.

Other reasons that can contribute to why people with diabetes may feel sleepy after eating may include:

  • Overweight or obesity
  • Poor sleep quality
  • Mental and emotional issues that come from diabetes
  • Lack of adequate exercise
  • Non-compliance with treatment regimen
  • Medication side effects
  • Poor glucose control

Common signs and symptoms of diabetes

The following are common signs and symptoms of diabetes, which, when present together with the feeling of tiredness or sleepiness after meals, may indicate that a person has diabetes:

  • Frequent urination
  • Excessive thirst
  • Increased hunger
  • Unexplained weight loss
  • Blurry vision
  • Constant feeling of fatigue or tiredness
  • Slow healing of wounds
  • Numbness/tingling of hands/feet
  • Increased blood sugar level

Other reasons why you may feel sleepy after eating

Diabetes is not the only reason one may feel sleepy or tired after eating. Constantly feeling sleepy after eating may also be due to the body's normal activities or an underlying health condition. Here are some possible reasons why you may feel tired or sleepy after a meal:

1. The body's digestive process

Energy is used for every activity of the body, including digestion. When you eat, your body expends energy in the breakdown and metabolism of the food. This may lead to a drop in energy and a subsequent feeling of tiredness immediately after a meal.

Also, when food is consumed, your body diverts blood flow to the digestive organs to facilitate the breakdown of food and the absorption of nutrients.

This change in blood flow may lead to a temporary decrease in blood flow to other parts of the body, including the brain and muscles, which may contribute to feelings of fatigue.

2. Hypothyroidism

The thyroid gland plays a crucial role in metabolism. In people with hypothyroidism, their thyroid gland doesn't produce enough thyroid hormone, leading to a slowdown in metabolism.

As a result, the energy produced and utilized within cells may be reduced, leading to fatigue and drowsiness, particularly after meals when there's an increased demand for energy due to digestion.

3. Meal Composition

Meals high in fat and protein can take longer to digest compared to carbohydrate-rich meals. The process of breaking down these macronutrients requires more energy expenditure by the body, which can contribute to feelings of fatigue after eating.

Additionally, diets high in simple sugars, like cakes, can cause a blood sugar crash, causing a sudden drop in sugar levels, which may stimulate the feeling of sleepiness within minutes after a meal

4. Anemia

Anemia is the deficiency of red blood cells or hemoglobin in the blood, which can be caused by iron deficiency. Hemoglobin, a protein found in red blood cells, is responsible for transporting oxygen from the lungs to the body's tissues.

In anemia, the blood's oxygen-carrying capacity is decreased, leading to inadequate oxygen delivery to cells and tissues. This reduced oxygen availability can result in feelings of fatigue and lethargy, which may be more pronounced after meals when energy demands increase due to digestion.

5. Dehydration

Inadequate hydration can impair various bodily functions, including digestion and nutrient absorption. Additionally, dehydration can lead to decreased blood volume and reduced circulation, which may exacerbate feelings of fatigue after eating.

6. Sleep Disorders

Conditions like sleep apnea disrupt normal sleep patterns, leading to poor-quality sleep. This can result in excessive daytime sleepiness, which may worsen after eating due to the body's increased focus on digestion, diverting energy away from maintaining wakefulness.

7. Medication

Certain medications, such as antihistamines, sedatives, or opioids, can cause fatigue/drowsiness as a side effect. Taking these medications with food may exacerbate feelings of sleepiness, as digestion can further enhance their sedative effects.

8. Chronic Fatigue Syndrome (CFS)

CFS is a complex disorder characterized by profound fatigue that persists for six months or more and is not alleviated by rest. While the exact cause of CFS is not fully understood, it's believed to result from a dysfunction in the immune system, hormonal imbalances, and abnormalities in the nervous system.

Postprandial somnolence can be a symptom of CFS, possibly due to the body's struggle to meet the increased energy demands of digestion.

What people with diabetes can do to prevent sleepiness after eating

To prevent this feeling of sleepiness after meals, here are some tips that might help you:

  • Adhere to your diabetes-recommended diets.
  • Maintain a healthier weight.
  • Stay hydrated.
  • Eat smaller portions of food; large portions may increase the body's energy demand.
  • Improve the quality of your night's sleep.
  • Manage and limit stress.
  • Engage in adequate exercises.
  • Limit consumption of simple sugars like cakes or processed foods.
  • Avoid/limit your intake of alcohol, especially when eating.
  • Monitor your blood sugar levels regularly or as recommended by your healthcare provider.

When to see a doctor about your sleep concerns

Feeling sleepy or tired after eating can be normal, especially when the body is stressed out. However, if it becomes frequent, interferes with daily activities, and is accompanied by other unusual symptoms, it's best to see a doctor for proper evaluation, diagnosis, and treatment. 

Frequently Asked Questions (FAQs)

Is feeling sick after eating sugar a sign of diabetes?

If your blood sugar is normal, the feeling of sickness is likely not related to diabetes. Nonetheless, excessive sugar consumption is medically not advisable.

While the consistent feeling of sickness doesn't necessarily mean you have diabetes, it's worth discussing with your doctor, especially if it occurs frequently or with other diabetes-related signs.

Will high blood sugar make you feel tired?

Hyperglycemia (high blood glucose) can lead to fatigue because, in most cases, the cells are deprived of glucose (the cell's fuel source), as there may not be enough insulin to transport glucose to the cells. Without glucose, the cells are unable to generate energy, leaving a person feeling tired.