O believers! Fasting is prescribed for you—as it was for those before you1—so perhaps you will become mindful ˹of Allah˺. ˹Fast a˺ prescribed number of days.1 But whoever of you is ill or on a journey, then ˹let them fast˺ an equal number of days ˹after Ramaḍân˺. For those who can only fast with extreme difficulty,2 compensation can be made by feeding a needy person ˹for every day not fasted˺. But whoever volunteers to give more, it is better for them. And to fast is better for you, if only you knew. Ramaḍân is the month in which the Quran was revealed as a guide for humanity with clear proofs of guidance and the decisive authority. So whoever is present this month, let them fast. But whoever is ill or on a journey, then ˹let them fast˺ an equal number of days ˹after Ramaḍân˺. Allah intends ease for you, not hardship, so that you may complete the prescribed period and proclaim the greatness of Allah for guiding you, and perhaps you will be grateful.
Why Does Diabetic Blood Sugar Go Up When Fasting?
Fasting is often associated with lowering blood sugar levels, but for some diabetics, blood sugar may rise during fasting periods. This can be confusing, especially for those observing Ramadan or intermittent fasting for health reasons. Understanding why this happens can help individuals with diabetes manage their blood sugar more effectively while fasting.
Why Does Blood Sugar Rise During Fasting?
1. The Dawn Phenomenon (Fajr Effect)
In the early morning hours (usually between 3 AM and 8 AM), the body releases hormones like cortisol, growth hormone, and adrenaline to prepare for waking up. These hormones trigger the liver to release stored glucose, causing blood sugar to rise naturally. This effect is stronger in diabetics because insulin function is impaired, leading to higher-than-normal fasting blood sugar levels.
2. Liver Glucose Release (Gluconeogenesis)
During fasting, when the body isn’t receiving food, the liver compensates by breaking down stored glycogen and producing new glucose through a process called gluconeogenesis.
In non-diabetics, insulin regulates this process.
In diabetics, insulin resistance or deficiency means glucose production continues unchecked, leading to high fasting blood sugar.
3. Stress Hormones and Dehydration
Fasting can cause mild physical stress, especially in the first few days. The body responds by releasing stress hormones like cortisol, which can raise blood sugar.
Dehydration during fasting thickens the blood, making glucose more concentrated, leading to higher readings.
4. Insulin Resistance
In people with Type 2 diabetes, insulin resistance means that cells don’t respond well to insulin, making it harder for the body to use glucose properly. As a result, fasting blood sugar levels remain high, even without food intake.
5. Rebound Effect from Low Blood Sugar (Somogyi Effect)
If a diabetic person experiences low blood sugar (hypoglycemia) while fasting, the body reacts by releasing extra glucose from the liver as a protective mechanism. This can cause a blood sugar spike later, even if no food has been consumed.
How to Prevent Blood Sugar from Rising During Fasting
If you have diabetes and notice high blood sugar levels while fasting, here are some ways to manage it effectively:
1. Eat a Balanced Suhoor (Pre-Dawn Meal)
Include complex carbohydrates (oats, whole grains) for slow energy release.
Eat healthy fats (avocados, nuts) to slow glucose absorption.
Choose lean proteins (eggs, yogurt) to maintain satiety.
Avoid refined sugars and white bread, which cause blood sugar spikes.
2. Stay Hydrated
Drink 8–10 glasses of water between Iftar and Suhoor to prevent dehydration-related sugar spikes.
Avoid excessive caffeine (tea/coffee) as it can lead to dehydration.
3. Monitor Blood Sugar Levels
Check fasting blood sugar regularly to understand how your body reacts to fasting.
If your sugar levels are consistently high, consult a doctor for medication adjustments.
4. Be Mindful of Iftar Meals
Break your fast slowly with dates and water, then wait a few minutes before eating a full meal.
Avoid overeating or consuming high-carb, high-fat meals immediately after fasting.
Include fibre-rich vegetables and lean protein to stabilize blood sugar levels.
5. Consult a Doctor
If fasting blood sugar levels remain high despite precautions, your doctor may adjust your diabetes medication or insulin dosage.
Conclusion
For diabetics, fasting can sometimes cause unexpected blood sugar increases due to hormonal changes, liver glucose release, dehydration, or insulin resistance. While this may seem counterintuitive, understanding the causes can help manage it effectively. By staying hydrated, eating a balanced Suhoor, and monitoring blood sugar levels, diabetics can fast more safely. However, always consult a healthcare provider before fasting to ensure proper diabetes management.
FAQs
Why does my fasting blood sugar go up even when I don’t eat?
Your liver releases stored glucose during fasting due to hormonal changes (Dawn Phenomenon) or gluconeogenesis, especially in diabetics with insulin resistance.
How can I prevent high blood sugar when fasting?
Drink plenty of water, eat a balanced Suhoor, monitor blood sugar levels, and avoid processed carbs or overeating at Iftar.
Should diabetics fast during Ramadan?
It depends on individual health conditions. Some diabetics can fast safely with medical guidance, while others, especially those on insulin, may need special adjustments.
What is the difference between the Dawn Phenomenon and the Somogyi Effect?
Dawn Phenomenon: Morning blood sugar rises due to hormonal activity (normal in diabetics).
Somogyi Effect: Blood sugar rebounds after a nighttime low, caused by excessive insulin or skipping meals.
Should I change my diabetes medication while fasting?
Only adjust your medication under doctor supervision. Some medications may need dosage changes to prevent extreme blood sugar fluctuations.
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