Diabetes and Ramadan fasting — the clinical protocol

Diabetes and Ramadan fasting interact in ways that make the month medically complex for approximately 50 million Muslims with diabetes worldwide. Fasting from pre-dawn (Suhoor) to sunset (Iftar) for 29–30 days fundamentally changes meal timing, carbohydrate distribution, hydration status, and insulin pharmacokinetics — all of which directly affect glucose control. The Epidemiology of Diabetes and Ramadan (EPIDIAR) study, involving 12,243 patients across 13 countries, found that the risk of severe hypoglycemia was 7.5 times higher during Ramadan for people with Type 2 diabetes on sulfonylureas, and 4.7 times higher for Type 1 patients who did not adjust their insulin protocol. The good news is that with proper pre-Ramadan clinical assessment (conducted 1–3 months before the fast begins), medication adjustment, and structured self-monitoring, most people with well-controlled Type 2 diabetes can fast safely. Type 1 patients carry a higher risk and require more intensive protocol adjustments. The International Diabetes Federation and Diabetes and Ramadan (DAR) International Alliance have published evidence-based protocols — this guide summarises the clinical framework in practical, actionable terms.

Pre-Ramadan risk stratification — who can fast safely

The IDF-DAR International Alliance publishes a structured risk stratification tool that classifies patients into four categories based on clinical risk factors. This classification determines whether fasting is advisable, possible with modification, or contraindicated from a medical standpoint — while acknowledging that the final decision rests with the patient and their religious obligations.¹

Very high risk — fasting not medically advisable:

• Type 1 diabetes with HbA1c above 10%
• Recurrent severe hypoglycemia in the preceding 3 months (more than one episode requiring external assistance)
• Hypoglycemia unawareness (absent or attenuated autonomic warning symptoms)
• Diabetic ketoacidosis (DKA) episode in the preceding 3 months
• Hyperosmolar hyperglycaemic state in the preceding 3 months
• Pregnancy with diabetes
• Acute intercurrent illness
• Type 2 diabetes on high-dose sulfonylurea with poor glycaemic control (HbA1c above 10%)

This category should not fast from a medical standpoint. “Advised against fasting” is not a religious ruling — it is a medical risk statement. Many patients in this category choose to fast regardless; the clinical obligation is to ensure they understand the risks in specific quantitative terms and have a clear protocol for breaking the fast and seeking emergency care.

High risk — can fast with intensive medical supervision and protocol modification:

• Type 1 diabetes with reasonable control (HbA1c 7–10%)
• Type 2 diabetes with HbA1c 7.5–10% on insulin or sulfonylurea
• Chronic kidney disease stage 3 or above with diabetes
• Cardiovascular disease with diabetes

Moderate risk — can fast with adjusted medication protocol and regular monitoring:

• Type 2 diabetes on metformin, DPP-4 inhibitors, GLP-1 agonists, or SGLT2 inhibitors (with specific SGLT2 caveats — see below)
• Type 2 diabetes with HbA1c below 7.5% on oral agents

Low risk — can fast with standard precautions:

• Type 2 diabetes managed with diet alone or with metformin monotherapy
• Good metabolic control (HbA1c below 7%)
• No history of hypoglycemia

The pre-Ramadan clinical assessment should occur 1–3 months before Ramadan begins, not in the final days before. This window allows time for medication switches (sulfonylurea to safer alternative), dose titration, and patient education about glucose monitoring and fast-breaking thresholds. A rushed assessment the week before Ramadan is insufficient for high- or very-high-risk patients.

Insulin adjustment protocols for Ramadan — Type 1 and Type 2

Insulin pharmacokinetics during Ramadan fasting must account for two major changes: the prolonged fasting window (typically 12–18 hours depending on latitude and season) and the shift of caloric intake to two main meals (Suhoor and Iftar) with the majority of carbohydrates concentrated at Iftar.²

Type 1 diabetes — basal-bolus regimen: The standard IDF-DAR recommendation for Type 1 patients on long-acting basal insulin (glargine U100, detemir, or degludec) with rapid-acting bolus insulin is:

• Reduce the total basal insulin dose by 20–40% during Ramadan
• Shift the larger meal bolus to Iftar (the largest carbohydrate meal of the day)
• Use a small bolus at Suhoor proportional to the Suhoor carbohydrate content
• For patients on an insulin pump (CSII), discuss temporary basal rate reduction with their diabetes care team — typically a 20–30% reduction during the fasting hours

The 20–40% basal reduction range reflects individual variability. Patients with higher baseline insulin requirements and more insulin resistance need smaller percentage reductions; those with more labile control need larger reductions and more frequent monitoring during the fasting period. These reductions should be established through close contact with the diabetes care team during the first week of Ramadan and adjusted based on monitored glucose patterns — not applied as a single fixed reduction for the entire month.

Type 2 diabetes — once-daily basal insulin: For patients on once-daily basal insulin only, the primary adjustment is timing: shifting the injection from bedtime or morning to pre-Iftar (approximately 30 minutes before breaking fast). This aligns the insulin’s peak activity with the highest carbohydrate load of the day. Dose reduction of 20–30% is typically appropriate to reduce hypoglycemia risk during the prolonged fasting period.

Type 2 diabetes — premixed insulin: Premixed insulins (e.g., 70/30 NPH/regular, biphasic aspart) are more complex to adjust because their fixed ratio cannot be easily titrated to the Ramadan meal pattern. The IDF-DAR guidance recommends switching from twice-daily premixed to basal-bolus regimens before Ramadan for high-risk patients, as premixed insulins carry higher hypoglycemia risk in fasting conditions.

Oral medication adjustments — sulfonylureas, SGLT2s, and metformin

The sulfonylurea class (glibenclamide/glyburide, glimepiride, glipizide) carries the highest hypoglycemia risk of any oral diabetes medication during Ramadan because it stimulates insulin secretion independently of food intake. When a patient on a sulfonylurea fasts for 14–16 hours, insulin secretion continues, creating a glucose-lowering pressure without the counterbalancing glucose from food. The EPIDIAR study’s 7.5-fold increase in severe hypoglycemia for Type 2 patients is largely attributable to this class.¹

Sulfonylurea recommendations for Ramadan:

• Ideal: switch to a lower-risk alternative (DPP-4 inhibitor, GLP-1 agonist, or gliclazide modified-release at a reduced dose) at least 4–6 weeks before Ramadan to allow stabilisation
• If switching is not possible: reduce the sulfonylurea dose by at least 50%, take only at Iftar, and do not take the Suhoor dose
• Gliclazide modified-release is the lowest-risk sulfonylurea during fasting if a switch is not feasible, as its gradual release profile produces a lower hypoglycemia risk than short-acting sulfonylureas

SGLT2 inhibitors (dapagliflozin, empagliflozin, canagliflozin): SGLT2 inhibitors carry a risk of euglycaemic DKA during prolonged fasting that is disproportionate to their blood glucose effects. Fasting reduces carbohydrate intake, which lowers glucose and insulin levels while glucagon rises — conditions that promote ketogenesis. SGLT2 inhibitors suppress renal glucose reabsorption and further reduce insulin secretory drive. The combination produces elevated ketone levels even in patients with Type 2 diabetes who have some residual beta-cell function. Most IDF-DAR guidelines advise against SGLT2 inhibitor use during Ramadan, or recommend stopping the medication for the duration of the fast with physician supervision.²

Metformin: No significant dose adjustment is required during Ramadan for patients tolerating metformin well. The primary consideration is timing: metformin should be taken with meals to minimise gastrointestinal side effects. For patients on twice-daily dosing, redistribute to Iftar and Suhoor. For patients on extended-release once-daily metformin, taking it with Iftar is appropriate.

DPP-4 inhibitors and GLP-1 agonists: These classes have very low intrinsic hypoglycemia risk because they are glucose-dependent (DPP-4 inhibitors) or produce satiety-mediated effects on food intake (GLP-1 agonists). No dose adjustment is typically required during Ramadan. GLP-1 agonists may contribute to reduced Suhoor and Iftar caloric intake through satiety effects, which is generally beneficial for glucose management.

Suhoor and Iftar meal composition — the carbohydrate framework

Meal composition during Ramadan profoundly affects glucose stability throughout the fasting day and the post-Iftar period. The two-meal structure creates a natural experiment in carbohydrate timing that has been studied specifically in the Ramadan diabetes context.³

Suhoor (pre-dawn meal) — the slow-release carbohydrate window: Suhoor should provide sustained glucose delivery through the fasting hours, which means prioritising slow-digesting, high-fiber carbohydrates over fast-digesting refined starches or sugary foods. Evidence-based Suhoor composition:

• Oats (porridge or overnight oats): GI approximately 55–58, high beta-glucan content slows digestion and provides stable glucose for 4–6 hours post-meal. A 50 g dry weight serving provides approximately 30 g carbohydrate and 4 g beta-glucan fiber.
• Whole grain bread or pitta: GI approximately 50–60, preferable to white bread (GI 70–75) for sustained glucose delivery.
• Low-fat yoghurt: 10–15 g carbohydrate per 150 g serving, low GI, high protein for satiety.
• Legumes (lentils, chickpeas): GI 25–40, high fiber and protein. A 150 g bowl of cooked lentils provides 20 g carbohydrate with GI approximately 30 and excellent satiety.
• Eggs (2–3): Protein only, no carbohydrate impact, excellent satiety.

Suhoor target carbohydrate: 30–45 g for most Type 2 patients, adjusted based on medication and monitoring data. Simple sugars, fruit juice, and refined cereals at Suhoor produce a glucose spike followed by a trough in the early fasting hours — exactly the pattern that generates hypoglycemia risk.

Iftar (breaking fast) — the traditional beginning: The prophetic tradition of breaking fast with dates and water is medically compatible with diabetes management in controlled quantities. Two to three dates (approximately 20–25 g carbohydrate, GI 42–65 depending on variety) provide rapid glucose recovery from the fasting state without the degree of spiking produced by larger carbohydrate loads. Post-dates, rest 20–30 minutes before the main Iftar meal — this allows initial glucose recovery and prevents the rapid gastric emptying that comes with eating into a completely empty stomach.

The main Iftar meal should be balanced: a moderate portion of lean protein, a serving of vegetables, and a controlled carbohydrate portion (50–70 g carbohydrate for most Type 2 patients). Avoid large single-carbohydrate loads such as a full portion of biryani or rice with bread simultaneously — these produce glucose excursions that are difficult to manage even with appropriate insulin dosing.

Blood glucose monitoring during the fasting hours

A common misconception is that blood glucose monitoring (finger-stick or CGM) breaks the Ramadan fast by introducing something into the body. The predominant scholarly opinion, endorsed by Dar al-Ifta in Egypt and multiple Islamic scholarly bodies, is that blood draws and finger-stick glucose testing do not break the fast because the amount of blood involved is negligible and the act is medicinal rather than nutritive.⁴ Patients should consult their own religious authority if they have specific concerns, but most will receive permission to monitor.

The recommended glucose monitoring schedule during Ramadan for insulin-treated patients:

• Pre-Suhoor: Establish the baseline before eating; if glucose is below 80 mg/dL before Suhoor, consider additional protein or a small amount of slow-digesting carbohydrate
• Mid-fasting (approximately 6 hours post-Suhoor): Check for early hypoglycemia; if glucose is below 70 mg/dL, the fast should be broken
• 2 hours pre-Iftar: Warning check; if glucose is below 70 mg/dL, the fast must be broken immediately
• 2 hours post-Iftar: Assess post-meal glucose response to Iftar composition; should guide next day’s meal structure

Mandatory fast-breaking glucose thresholds (IDF-DAR consensus):

• Blood glucose below 70 mg/dL at any measurement: break the fast immediately
• Blood glucose above 300 mg/dL: break the fast and seek medical assessment — this is early-stage DKA territory
• Symptoms of hypoglycemia (sweating, trembling, confusion) regardless of meter reading: break the fast

Breaking the fast for medical reasons is explicitly permitted in Islamic jurisprudence (the principle of darura, necessity) and does not negate the month’s spiritual practice. The IDF-DAR patient education materials, available in 13 languages, explain this explicitly and are designed to be shared with patients who may have reservations about breaking the fast for medical reasons.

Post-Ramadan insulin and medication review

Returning to normal eating patterns after Ramadan requires medication re-titration that is as important as the pre-Ramadan adjustment. The evidence on intermittent fasting in Type 2 diabetes more broadly suggests that the re-feeding transition deserves as much clinical attention as the fasting period itself. Insulin doses and oral medication regimens reduced for fasting will no longer be appropriate once three full meals per day resume, and the risk of hyperglycemia in the weeks after Ramadan is real — sometimes more concerning clinically than the Ramadan hypoglycemia risk.²

The post-Ramadan follow-up appointment should occur within 1–2 weeks of Eid al-Fitr. Key review points:

• Restore medication doses to pre-Ramadan levels unless clinical data from the month indicate that lower doses produced better-than-expected control (in which case, evaluate whether the Ramadan doses represent a sustainable lower-dose strategy)
• Assess weight change: Ramadan frequently produces 1–3 kg weight change in either direction depending on Iftar meal composition. Net weight loss may warrant a lasting medication dose reduction rather than full return to pre-Ramadan doses
• Review glucose log or CGM data from the month to identify patterns: which days were highest-risk for hypoglycemia, which meal compositions produced the best glucose profiles
• If a medication switch was made pre-Ramadan (e.g., from sulfonylurea to DPP-4 inhibitor), evaluate whether to maintain the switch rather than reverting — the medication change may represent an opportunity to make a lasting improvement in the regimen

References

1. Al-Arouj M, Assaad-Khalil S, Buse J, et al. “Recommendations for Management of Diabetes During Ramadan: Update 2010.” Diabetes Care 33, no. 8 (2010): 1895–1902. (EPIDIAR study data cited.)

2. Hassanein M, Al-Arouj M, Hamdan M, et al. “Diabetes and Ramadan: Practical Guidelines.” Diabetes Research and Clinical Practice 126 (2017): 303–316. (IDF-DAR International Alliance.)

3. Benaji B, Mounib N, Roky R, et al. “Diabetes and Ramadan: Review of the Literature.” Diabetes Research and Clinical Practice 73, no. 2 (2006): 117–125.

4. Bravis V, Hui E, Salih S, et al. “Ramadan Education and Awareness in Diabetes (READ) Programme for Muslims with Type 2 Diabetes Who Fast During Ramadan.” Diabetic Medicine 27, no. 3 (2010): 327–331.

5. Taha S, Younis A, Galal A, et al. “Dietary Patterns and Glycemic Control in Muslim Patients with Type 2 Diabetes During Ramadan.” Journal of Diabetes Research 2020: 5396790.