Are Religious Fasts Safe for People With Diabetes?

When you have diabetes, you know you have to keep a careful eye on what you eat and how it impacts your blood sugar. But if you’re part of a faith community that observes religious fasting holidays, you may be left wondering: Can you safely take part, or do you have to sit them out?

“Many people with diabetes are able to fast safely and enjoy the full spiritual, physical and mental health benefits of religious fasts, provided they’re medically cleared and take some necessary precautions,” says endocrinologist Hasan Husni, MD.

Dr. Husni offers wellness tips for fasting holidays and explains why it’s so important to know your blood sugar numbers — plus, how new technology can help.

Is it safe to fast when you have diabetes?

Before you participate in a religious fast, you should talk with your diabetes management team to make sure it’s safe for you to do so.

“During this consultation, your care team can advise you on any medication adjustments, how to monitor your blood sugar levels while you’re fasting, and in which circumstances you may need to break your fast,” Dr. Husni says.

Fasting not only alters the timing of meals, but it can also affect many other elements of your everyday life, including:

• Dietary habits.
• Circadian rhythms.
• Physical activity.
• Sleeping patterns.

“Lifestyle factors like diet, excess weight, smoking and lack of physical activity can all have a negative impact on your blood sugar and insulin levels, which can make diabetes more difficult to manage,” Dr. Husni says.

“A fasting holiday can provide an opportunity to focus on adopting healthy habits that reduce or eliminate these diabetes risk factors, while also reducing cholesterol levels and improving cardiovascular health.”

Plan ahead for fasting holidays by using these five strategies.

1. Be vigilant about monitoring your blood sugar

When you’re fasting, it’s especially important to monitor your blood sugar.

“While you have diabetes and you participate in a fast, you’re at greater risk for the dangers of very high or low blood sugar levels, as well as for dehydration,” Dr. Husni shares.

Another serious complication is diabetes-related ketoacidosis, a life-threatening condition that occurs when your body doesn’t have enough insulin to use sugar for energy. Instead, it breaks down fat, releasing ketones that build up and cause your blood to turn acidic.

To reduce these risks, it’s important to regularly monitor your blood sugar throughout your fast.

“If you want to minimize the need for finger pricking, ask your healthcare provider about continuous glucose monitoring,” Dr. Husni suggests. “This is a small, temporary and wearable device that measures glucose levels 24 hours a day. You typically replace it every 10 to 14 days, or as needed.”

2. Recognize warning signs

In addition to monitoring your blood sugar, check in with yourself throughout your fast — and be sure you know the warning signs of high or low blood sugar so that you know if you’re experiencing a medical emergency that will require you to break your fast.

Some of the most common signs of low blood sugar (hypoglycemia) are:

• Shakiness or trembling.
• Weakness.
• Sweating and/or chills.
• Feeling extremely hungry.
• Sped-up heart rate.
• Dizziness or lightheadedness.
• Confusion or trouble concentrating.
• Anxiety or irritability.
• Color draining from your skin.
• Tingling or numbness in your lips, tongue or cheeks.

Symptoms of high blood sugar (hyperglycemia) include:

• Blurred vision.
• Frequent urination.
• Headache.
• Increased thirst and/or hunger.

“If you start to experience any of these symptoms, test your blood sugar immediately,” Dr. Husni advises. “In general, you’ll need to break your fast if your blood glucose is lower than 70 mg/dl (3.9 mmol/l) or higher than 300 mg/dl (16.7 mmol/l).”

Some people, he notes, may need to break their fast at different blood glucose levels depending on their age and overall health, so it’s important to discuss this ahead of time with your diabetes management team.

3. Break your fast carefully

It’s always best to break your fast with a healthy meal that will help hydrate you and restore your strength. And it’s important not to gobble it down.

“It can be challenging to resist the temptation to have a very large meal at iftar. Additionally, people often break their fasts by eating quickly, which can lead to overeating,” Dr. Husni says. “It takes 15 to 30 minutes for the satiety signal to reach the brain.” This can make it difficult to tell when you’re full.

Plus, he adds that some people actually gain weight during long-term fasting holidays like Ramadan, as a result of factors like being less active, eating carb-heavy foods at iftar and snacking throughout non-fasting hours.

If you have diabetes and are observing Ramadan, consider working with a nutritionist who’s experienced in diabetes education.

“They’ll determine your daily calorie needs for weight loss or weight maintenance, whichever the case may be,” Dr. Husni says, “and they can help you create a sustainable meal plan or strategy that ensures that you’re getting the correct balance of macronutrients, including proteins, fats and carbohydrates, at suhoor and iftar.”

Generally, he recommends consuming around 40% to 50% of your daily calorie intake at iftar; around 30% to 40% at suhoor; and the remainder as a snack at night.

4. Stay hydrated during non-fasting hours

Dehydration is a major risk during fasting holidays, especially if you’re doing a dry fast that doesn’t allow you to drink water.

“It’s important to drink adequate amounts of water during non-fasting hours and to limit your intake of caffeine-based or sugary drinks,” Dr. Husni stresses. “This is especially true in areas with hot climates or long daylight hours, where the risk of dehydration and diabetes-related ketoacidosis is greater.”

5. Get some exercise

In general, physical activity brings all kinds of benefits, including helping regulate blood sugar, weight management and supporting cardiovascular health. But when you have diabetes, it’s best to talk to your healthcare provider ahead of time about exercising during a religious fast.

“Exercise should only be undertaken carefully, particularly if you take insulin,” he says, “because it can put you at a higher risk of having low blood sugar when you exercise.”

It’s best to stick to low- to moderate-intensity physical activity rather than going all-out with a hardcore sweat session.

“During Ramadan, for example, we generally recommend walking as a safe way to exercise, preferably after iftar,” he adds.

Diabetes doesn’t necessarily require you to skip your fast

While some people with diabetes seek a religious exemption from fasting, many can safely participate. It should always be a shared decision between you, your physician and your religious leader.

From a medical perspective, Dr. Husni emphasizes checking in with your diabetes care team ahead of time to be sure you’re approaching fasting in the healthiest way possible.

“Religious fasting holidays, especially longer-term ones like Ramadan, can be a wonderful time to embrace healthy habits that you can build on once the fasting period is finished for long-term health benefits,” he says.