The effect of fasting Ramadan on type 2 diabetes: A narrative review and practice update

ABSTRACT

Ramadan fasting, observed by Muslims worldwide for over 1,400 years, involves abstaining from food, drink, and other physical needs from dawn to sunset. Despite exemptions for individuals with chronic conditions, many patients with type 2 diabetes mellitus (T2DM) choose to fast, raising concerns regarding safety and metabolic control. To synthesize recent literature (2021-2024) on the physiological impact of Ramadan fasting on individuals with T2DM and offer evidence-based recommendations for safe fasting practices. This narrative review evaluates recent clinical studies on the effects of Ramadan fasting in T2DM patients. Key areas include metabolic outcomes, potential risks, and strategies for pre-Ramadan assessment and individualized care. Emerging evidence suggests that Ramadan fasting may offer metabolic benefits to T2DM patients, including improved insulin sensitivity, reductions in body weight, fat mass, blood pressure, and proinflammatory cytokines. Positive changes in gut microbiota and hormonal regulation have also been reported. However, without proper medical oversight, fasting may increase the risk of hypoglycemia, hyperglycemia, dehydration, and diabetic ketoacidosis. The physiological mechanisms of Ramadan fasting align with those of nonreligious intermittent fasting, which also show favorable outcomes in glucose and lipid regulation. Ramadan fasting can be safe and beneficial for many with T2DM when properly managed. Pre-Ramadan planning—including risk assessment, medication adjustments, and education—should begin 6-8 weeks in advance to reduce risks and guide informed decisions.

Introduction

Ramadan, a holy month observed by over a billion Muslims worldwide, involves daily fasting that significantly alters metabolic, nutritional, and behavioral patterns. Understanding these changes is essential for clinicians managing patients with chronic illnesses, particularly diabetes..

Ramadan Definition and Significance

Ramadan fasting, or Sawm, is a central religious obligation in Islam, practiced annually for over 1,400 years as prescribed in the Quran. As one of the Five Pillars of Islam, it symbolizes spiritual discipline, self-control, and communal solidarity.[1] During the month of Ramadan, Muslims abstain from food, drink, smoking, and sexual activity from dawn (Al-Fajr) until sunset (Al-Maghrib). Most individuals consume two main meals: Suhoor (predawn) and Iftar (postsunset), which often serve as social gatherings with family and community.[2]

While fasting is obligatory for healthy adult Muslims, exemptions are granted to prepubertal children, menstruating women, pregnant or breastfeeding individuals, travelers, and those with physical or mental illness. Even so, many individuals with chronic or acute diseases, particularly diabetes, choose to fast, which may affect their health.[3,4] Those who are exempt from fasting are encouraged to make up missed days or perform alternative charitable acts, depending on their circumstances. Ramadan not only affects spiritual life but also induces significant shifts in lifestyle and physiology. Changes include alterations in caloric and macronutrient intake, hydration status, sleep-wake cycles, and daily routines, all of which can influence metabolic regulation and overall health.[5,6] It has been observed that body weight, sleep quality, and circadian rhythms are less aligned at this time.[2] Such changes would be especially relevant to those with chronic metabolic diseases like type 2 diabetes mellitus because shifted meal timing and altered eating patterns would have both positive and potentially even harmful consequences.[3] Being familiar with these dynamics is key to successful clinical management.

According to some studies, Ramadan Fasting can potentially lead to numerous health improvements, including the growth in levels of the gut microbiome and hormone balance, the drop in body weight, skeletal muscle mass, and fat levels, and the reduced levels of inflammation indicators, cholesterol, and triglycerides.[6,7] Other effects include a decrease in body mass index (BMI), waist circumference, and systolic and diastolic blood pressure in individuals subscribing to the fast.

Fasting during Ramadan has possible health risks, but it is still beneficial to healthy individuals; there exists orientations of chances of type 2 diabetes mellitus (T2DM), which is a more than one organ metabolic disorder. Diabetes patients are also more vulnerable to the development of problems observed during fasting, such as hypoglycemia, hyperglycemia, dehydration, and diabetic ketoacidosis (DKA), particularly in situations when fasting is conducted without medical attention and unpleasant treatment, and individual care plans.[8]

Diabetes Introduction and Epidemiology

Type 2 diabetes mellitus (T2DM) is a chronic metabolic condition that involves the permanent condition of hyperglycemia or high levels of glucose in the blood. It comes to nearly 90% of all cases of diabetes and has now emerged as one of the most common causes of endocrinological and metabolic disorders on a worldwide scale. According to an International Diabetes Federation (2021)[9] report, 537 million adults have been living with diabetes during the year 2021, and it is projected that the number of people with diabetes will rise to 783 million by 2045. The first process that contributes to the development of the disease is poor insulin secretion, which occurs due to the fact that the body cannot properly produce insulin. Due to obesity, high-calorie intake, physical inactivity, and genetic factors.[10,11] Explain why, because of obesity, high-calorie intake, physical inactivity, and genetic background, there occurs a two-fold process of 2-cell failure and insulin resistance. A combination of these causes poor glucose uptake and sustained hyperglycemia. T2DM could be asymptomatic in most people, which lengthens their time of diagnosis and puts them at risk of complications by the time their condition is diagnosed. The most important thing to note is that it has a multifactorial pathophysiology, and this enables it to be prevented and treated correctly.

T2DM is also linked to numerous complications that may be divided into macrovascular and microvascular ones. Macrovascular complications encompass coronary artery disease, cerebrovascular disease, and peripheral arterial disease, all of which increase the risk of cardiovascular events and death. The kidneys, eyes, and nerves are the most commonly affected systems by microvascular complications, which can lead to diabetic kidney disease (DKD), retinopathy, and peripheral neuropathy. The most noticeable of these is DKD, which afflicts a range of 40-59. Eight percent of those with T2DM.[12] The complications decrease the quality of life and have a considerable healthcare burden. Prevention or postponement of these outcomes is crucial through early detection, lifestyle modifications, and effective glycemic control.

Other Forms of Fasting

Intermittent fasting and other types of fasting have also been popularized as secular diet regimens that limit the amount of food consumed not by what is consumed but by when. Like Ramadan fasting, intermittent fasting is designed to optimize metabolic health over time rather than focusing on the content of food intake. There are two broad categories of intermittent fasting: alternate-day fasting and time-restricted feeding. Alternate-day fasting involves complete fasting or minimal caloric intake on specified days, with regular consumption on other days. The most popular variation of it is the 5:2 method, which consists of two nonconsecutive fast days and five days of unlimited eating. Time-restricted feeding, however, is a diet that requires one to take all their meals during a specific time frame, i.e., 16:8 (16 hours fast, 8 hours eat) or 20:4. Reported that intermittent fasting patterns can lead to significant health benefits,[13] including improved weight management, enhanced insulin sensitivity, and favorable changes in cardiovascular risk markers. Establishing a consistent fasting and feeding cycle is the central principle underlying both intermittent and Ramadan-related fasting practices [see Table 1].

Table 1.

Outlines two common approaches to intermittent fasting

Type	Definition
Alternative day fasting	Alternates 24-hour fasts with eating days. The 5:2 method involves two fasting days and five nonrestrictive eating days each week.
Time-restrictive fasting	Limits food intake to specific windows, e.g., a 16-hour fast followed by an 8-hour eating period.

Methods

The purpose of this narrative review was to assess the recent literature on the impact of Ramadan fasting on patients with Type 2 diabetes mellitus (T2DM), with an emphasis on the physiological outcomes and pre-Ramadan clinical management. The review was also intended to summarize new practices of risk stratification and patient education. This study was approved by the Institutional Review Board of Imam Mohammad Ibn Saud Islamic University (IMSIU) with registration number 660/2024, dated June 20, 2024.

A nonsystematic literature search was conducted using key databases, including PubMed, Google Scholar, and other scholarly search engines. The main keywords searched in various combinations were diabetes, type 2 diabetes, Ramadan, and fasting. The use of Boolean operators, such as AND and OR, was employed to narrow down search results and identify relevant studies.

Inclusion criteria were as follows: (1) primary research articles, (2) published in English, (3) from January 2021 onward, and (4) containing accessible abstracts. Studies were included if they examined the clinical, metabolic, or psychosocial effects of Ramadan fasting on patients with diabetes. Exclusion criteria included non-English publications without abstracts and articles based purely on secondary data (e.g. meta-analyses or editorials). The review selectively incorporated randomized controlled trials, observational studies, and cohort studies that met the inclusion criteria.

Physiology of Fasting and Its Metabolic Effects

Normal Physiology of Fasting and Sugar Regulation in Healthy Individuals.

It is essential to comprehend the fundamentals of glucose and fat metabolism, including the concept of metabolic switching, in the context of discussing the health-related outcomes of fasting [see Figure 1]. One of the classic models in this field is the glucose-fatty acid cycle, proposed by Randle et al.,[14] which describes the ability of fat and glucose to compete for oxidation in the cell based on whether the organism is in a fed or fasted state. Stockman et al.[15] list four phases of the metabolic cycle: the fed state, postabsorptive or early fasting, fasting, and starvation. During the fed state, most tissues use glucose as their primary fuel, and any excess glucose is either stored as glycogen or converted into fat. The triglycerides are stored as energy in adipose tissue.

Figure 1.

Physiology of fasting

During prolonged fasting, the body taps into its energy resources to sustain vital processes. The process breaks down triglycerides into free fatty acids and glycerol, which are then metabolized by the liver to produce energy. The liver also breaks down fatty acids into ketone bodies and gradually substitutes them as the primary fuel source for most organs, including the brain. This adaptation conserves glucose in glucose-dependent organs, including red blood cells and the renal segment. The utilization of fat and ketones during long-term fasting is a significant adaptive process in humans.[16]

The fed and postabsorptive states represent normal metabolic conditions in individuals who consume regular meals. In the fed state, insulin is the most abundant hormone that encourages the use of glucose, the production of glycogen, and the synthesis of fats. During fasting, glucagon becomes the primary mediator that activates hepatic glycogenolysis to maintain blood glucose levels. As soon as liver glycogen reserves are depleted, typically after 12-24 hours of food deprivation, the organism undergoes a metabolic shift, transitioning to a state of lipolysis and ketogenesis.[17] This adaptation occurs based on a negative energy balance, providing an unrelenting supply of energy to essential organs. The effective control of these metabolic transitions enables survival under intermittent or prolonged fasting conditions.

Alterations of Physiology in Diabetics

Sahin et al. (2013)[18] conducted a study on 88 patients with type 2 diabetes mellitus (T2DM) in Istanbul who chose to fast during Ramadan and measured metabolic indicators before and after the fasting period. Most of the parameters did not change significantly as a result of the study; however, there were more cases of hypoglycemia and hyperglycemia in the fasting group. Body weight, BMI, waist circumference, blood pressure, fructosamine (314.18 ± 75.40 vs. 314.49 ± 68.36 μmol/L), fasting insulin (12.61 ± 8.94 vs. 10.51 ± 6.26 μU/mL), and postprandial glucose (213.40). There was, however, a significant improvement in the microalbuminuria, which reduced significantly to 45.03-197.11 mg/dL. This suggests that Ramadan fasting may have renal protective effects in patients with type 2 diabetes mellitus (T2DM), possibly by enhancing metabolic regulation or sparing the kidneys from the dietary workload.

Ramadan fasting is also likely to influence physiological performance and energy metabolism along with glycemic and renal measures. A decrease in metabolism rate has been reported in the last week of Ramadan in Husain et al. (1987)[14] through a reduction of the oxygen consumption rate. Submaximal exercise oxygen consumption[19] and resting heart rate[20] are observed to be reduced in fasting individuals in other reports. These findings indicate that the body adapts to fasting by saving energy, and this may be an adaptation to the effects of fasting. Such changes can be considered a positive change in people with diabetes since they can increase energy efficiency and lower the metabolic burden. However, the extent of such benefits can be different according to individual factors, such as glycemic control, medication usage, and length of fasting. (See Figure 2 for a summary of physiological alterations in people with diabetes during Ramadan fasting.)

Figure 2.

Alteration of physiology in DM

Risk Stratification Pre-Ramadan

Risk stratification is the essential process in the safe management of diabetic patients planning to fast during Ramadan. It is undertaken before the holy month in order to reduce the possible complications and to achieve clinical success to the utmost [see Figure 3]. Additional factors that have an essential influence on this process are the type of illness, the number of fasting hours per day, the severity of complications, the treatment plan, comorbidities, and financial situations.[21] Based on these variables, the International Diabetes Federation and the Diabetes and Ramadan International Alliance (IDF-DAR) suggest that medical experts should develop a properly structured pre-Ramadan consultation at least 6-8 weeks before Ramadan.[22] During this session, physicians ought to find out the likelihood of a patient undergoing complications due to fasting and classify every patient as a low-, moderate-, or high-risk group. Through this grouping, clinicians will be in a position to give specific advice, such as the medical ability of the patient to fast and precautionary measures that should be taken. This stratification has a patient-centered model that improves safety and allows shared decision-making.

Figure 3.

Risk stratification pre-Ramadan

Validation of the IDF-DAR Risk Stratification Tool

The first validation study was an observational research carried out in Al-Madinah Al-Munawarah, Saudi Arabia, during the Ramadan season of 2021 to examine the effectiveness of the use of the IDF-DAR risk stratification tool in predicting the outcome of fasting in diabetic patients.[23] The sample size consisted of 466 patients, of whom 79.4% of the patients were type 2 diabetes mellitus (T2DM), whereas the other patients were type 1 diabetes mellitus (T1DM). It showed percentages of low risk, moderate risk, and high risk using the IDF-DAR scoring system of risk classification as 53.2, 70.4, and 76.4, respectively. Nevertheless, the rates of Ramadan fasting were 53.2% and 70.4%, respectively. Despite their respective groupings, kept fasting diaries and participated. Expected in post-Ramadan questionnaires, where they provided their symptoms and experiences. The study led to the determination that the IDF-DAR tool is valid and reliable in predicting poor outcomes, as evidenced by the significant increase in hypoglycemia and hyperglycemia incidences among high-risk individuals compared to moderate- and low-risk groups.

A second validation study, conducted as a prospective, survey-based assessment before and after Ramadan 2021, evaluated the predictive capacity of the updated IDF-DAR risk tool among fasting diabetic patients.[24] This study enrolled 659 patients, of whom 98.2% completed the follow-up after Ramadan. Among them, 91.5% had type 2 diabetes mellitus (T2DM,) and 8.5% had type 1 diabetes mellitus (T1DM). Based on the pre-Ramadan risk score, 51.4% were categorized as low risk, 26.3% as moderate risk, and 22.3% as high risk. Fasting adherence rates were highest in the low-risk group (94.3%), followed by the moderate-risk group (81.1%) and the high-risk group (76.9%), indicating a strong predictive alignment between risk category and ability to fast. Hypoglycemia was reported in 6.3% of low-risk, 21.9% of moderate-risk, and 35.0% of high-risk patients. These findings demonstrate a transparent gradient in fasting-related complications consistent with the IDF-DAR risk classification.

These severe hypoglycemia incidences were limited to the moderate- and high-threat index, with none noted in the low-threat subjects, suggesting again the discriminative characteristic of the tool. The distribution pattern was also similar to that of hyperglycemia, with 2.7%, 13.0%, and 23.8% of the individuals classified as low-, moderate-, and high-risk, respectively. The study also stated that risk assessment before Ramadan must be done on a case-by-case basis, especially among those with a complicated illness or therapy regimen. Overall, it is evident that the two articles have revealed the IDF-DAR risk stratification system to be a valid tool that can guide clinicians in advising patients with diabetes who intend to fast.

Emergency Admissions for Diabetic Exacerbations During Ramadan

The researchers performed retrospective cross-sectional research in a tertiary care military hospital in Jeddah, Saudi Arabia, in 2021, using diabetic patients who utilized the emergency care unit within the 9^th to 11^th lunar months of 2017-2018.[25] The number of emergency admissions made during this time was 24,498, with 0.84% of them being emergencies related to diabetes. Out of the 133 available patients, 45.9% were female and 54.1% male. About 73.7% of the patients were on insulin treatment, and 51.9% of the patients had type 2 diabetes mellitus (T2DM). Interestingly, the rate of diabetic emergencies in the lunar months differed in Shaban (7%), Ramadan (5%), and Shawwal (4%) (P = 0.001), indicating a decrease. However, no statistically significant variations were observed in patient profiles or demographics over the 3 months. The most common reason for hospitalization is hyperglycemia, particularly among T2DM patients using insulin, which means Ramadan fasting did not add to the diabetic-related emergencies.

A complementary prospective cross-sectional study conducted across 18 public hospitals in Malaysia between April and July 2019 also examined diabetes-related emergency admissions during Ramadan.[26] The study employed universal sampling and included adult Muslim patients with pre-existing diabetes who fasted or intended to fast and were admitted for diabetic ketoacidosis (DKA), hyperosmolar hyperglycemic state (HHS), or hypoglycemia. A total of 295 emergency admissions were recorded, with 119 occurring before Ramadan, 106 during Ramadan, and 70 after Ramadan. Two-thirds of admissions were due to hyperglycemic events. Hypoglycemia accounted for 37% of pre-Ramadan and 32.1% of Ramadan admissions. Contributing factors included the use of sulphonylureas (59.6%), the presence of nephropathy (54.5%), and a history of hypoglycemia (45.5%). The incidence of DKA was highest during Ramadan (36.1%), while HHS occurred more frequently in the pre-Ramadan period. Among hyperglycemic emergency admissions, 97.4% involved patients with type 2 diabetes mellitus (T2DM) for hyperosmolar hyperglycemic syndrome (HHS) and 75.9% for diabetic ketoacidosis (DKA). This study provided additional support for the view that Ramadan fasting does not increase diabetic emergencies but instead shifts the burden toward the pre-Ramadan period, likely due to insufficient preparation or medical oversight.

Notably, the Malaysian study also highlighted the limited use of pre-Ramadan education. Only a small proportion of patients with diabetes-related emergencies (31.5%) received medical advice regarding fasting during Ramadan.[26] This lack of systematic training may be a contributing factor to the higher rate of admission during the pre-Ramadan period, emphasizing the need for pre-Ramadan risk assessment and education, particularly among individuals on insulin or sulfonylureas and those with complications such as nephropathy. The two articles by Saudi and Malaysian scholars suggest that with proper planning and assistance, Ramadan fasting poses a significant minimal risk of diabetic crises. Instead, most complications are clustered in the pre-Ramadan period, suggesting that the absence of pre-Ramadan counseling or unadjusted medication could be a significant controllable risk factor. These findings support the clinical practicality of active interventions, including individualized risk stratification, dose adjustment, and structured education plans, in helping individuals with diabetes safely fast during Ramadan.

Mental Well-being and Energy Expenditure of Ramadan Fasting

Recent studies on Ramadan fasting have focused more on its psychological consequences and well-being, but the results have been inconsistent. In 2024, a randomized controlled trial conducted in Essen, Germany, and published in 2024 evaluated the impact of pre-Ramadan lifestyle preparation on the overall physical and psychological well-being of healthy Muslims.[27] A total of 114 Muslim adults, aged between 18 and 60 years, were randomly assigned to groups to undergo modified fasting (in which educational material on nutrition and lifestyle was provided before Ramadan) or fasting without intervention (a control group). Quality of life was also the primary outcome, measured using the WHO-5 Well-Being Index. The fasting group that made fasting modifications also reported significantly better well-being after Ramadan compared to the control group. Secondary effects included weight improvement, a lower body mass index, and reduced hip circumference, as well as improvements in diastolic blood pressure, perceived ease of life, and mindfulness. Although a relatively small percentage of participants experienced adverse effects, such as headaches, tiredness, and stomach pains, in both groups, there were no serious events directly attributed to the intervention or fasting itself.

The study concluded that with proper dietary and lifestyle preparation, Ramadan fasting may contribute to short-term enhancements in both physical and mental health for healthy Muslim adults.[27] Importantly, this effect appears more pronounced when structured educational interventions precede fasting. These findings support the broader role of Ramadan not only as a spiritual practice but also as a potential vehicle for promoting holistic wellness. However, the generalizability of these outcomes to individuals with chronic diseases, such as diabetes, remains limited, and further research is needed in high-risk populations. Nonetheless, this study emphasizes that structured education and intentional preparation can enhance the positive effects of fasting. Integrating mental health screening and well-being assessments in pre-Ramadan evaluations could offer an additional layer of patient-centered care, especially for individuals already managing chronic conditions.

In a separate 2024 study from Erzurum, Turkey, researchers investigated the impact of Ramadan fasting on energy expenditure and athletic performance in trained Muslim male athletes.[28] The study involved 14 participants (mean age: 22.4 years) who completed repeated sprint protocols under both fasting and nonfasting conditions. Each participant performed ten 20-meter sprints with 15-second recovery intervals in both states. Fasting trials were conducted after Suhoor following a 12-14-hour fast, while nonfasting trials were conducted at the same time of day outside Ramadan. Results showed that total metabolic energy expenditure (TEE) was slightly lower during fasting (236.5 ± 22 kJ) compared to nonfasting (245.2 ± 21.7 kJ), though this difference was not statistically significant. Similarly, per-sprint energy expenditure under fasting conditions (23.7 ± 2.2 kJ) was comparable to that of nonfasting conditions (24.5 ± 2.2 kJ). These results suggest that Ramadan fasting does not significantly impair short-duration anaerobic performance or total energy output in trained young males, supporting its metabolic tolerability These findings are summarized in Table 2.

Table 2.

Presents findings from two research studies examining the effects of Ramadan fasting on mental well-being, energy expenditure, and physical health

Aspect	Details
Research Focus	Mental well-being and energy expenditure during Ramadan fasting.
Study 1
Location	Essen, Germany
Participants	114 healthy adult Muslims (ages 18−60)
Groups	Modified fasting vs. control (usual Ramadan fasting)
Main Outcome	Quality of life measured by the WHO-5 Well-Being Index
Secondary Outcomes	Body weight, BMI, body fat percentage, waist-to-hip circumference ratio, blood pressure, heart rate, and adverse events.
Results	The modified fasting group reported a higher quality of life post-Ramadan. There were significant improvements in weight loss, BMI, diastolic blood pressure, quality of life, and mindfulness. There were no significant differences in adverse events (headaches, fatigue, etc.).
Conclusion	Following pre-Ramadan dietary and lifestyle recommendations can enhance physical and mental health in adult Muslims.
Study 2
Location	Erzurum, Türkiye
Participants	14 active male athletes (mean age 22.4, weight 69.5 kg, height 176 cm)
Method	Repeated sprint protocol during and after fasting.
Results	- Total metabolic energy expenditure (TEE) was slightly lower during fasting (236.5 kJ) vs. nonfasting (245.2 kJ) but not statistically significant. - Metabolic energy expenditure per sprint is also similar (23.7 kJ fasting vs. 24.5 kJ nonfasting).
Conclusion	There were no significant changes in metabolic outcomes and performance metrics between fasting and nonfasting conditions.

Recommendations for Managing Diabetic Patients Entering Ramadan

Effective management of diabetes during Ramadan should be done through well-organized instructions before the fasting period. Hassanein et al. (2021)[29] note that a complex assessment response must be performed 6-8 weeks before the onset of the sacred month. As a result of such an assessment, a healthcare professional (HCP) can obtain a comprehensive medical history, assess the level of diabetes management, and document comorbidities. The assessment of risk will then dictate whether a patient should or should not fast, which forms the foundation of clinical recommendations that may involve modifying medications, establishing a schedule to monitor blood glucose levels, and providing nutritional guidelines (as shown in Figure 4). Individualized plans should be provided to those permitted to fast, including the timing of medication administration, the frequency of glucose level checks, and the symptoms to be monitored. Post-Ramadan follow-up is also advised to evaluate the patient’s post-Ramadan outcome, address any concerns that may have developed during the fasting period, and identify any complications that may have arisen direction must be periodical, the researchers emphasize,[21] because safe fasting for one year does not and should not mean the same outcomes in future years of fasting.

Figure 4.

Recommendation for DM patients

Pre-Ramadan risk stratification and education should involve not only physicians and patients but also families and community members. Based on the IDF-DAR recommendations, relevant healthcare professionals (HCPs), especially primary care physicians, are expected to hold structured educational programs approximately 6-8 weeks before Ramadan.[22] During these sessions, patients should be categorized into three risk groups: low, moderate, and very high. The doctor will need to evaluate the effect of fasting on each patient’s clinical status and advise them accordingly. Education on self-monitoring of blood glucose levels, self-management of physical activity, identification of warning signs, and compliance with medication adjustments should all be provided on a patient-centered level. Teaching can be conducted in group sessions or individually. It has been seen that pre-Ramadan structured counseling has a substantial positive effect on hypoglycemia occurrence and fasting guidelines regularity. Most patients with T2DM can fast safely after proper knowledge and preparation to prevent dehydration, glycemic instability, and diabetic ketoacidosis.

Individuals in the very high-risk category, such as those with type 1 diabetes mellitus (T1DM), pregnant women with diabetes, or patients with severe complications, require close medical supervision if they choose to fast against medical advice. Such situations require Ramadan-specific education and monitoring. Physicians should emphasize the importance of conducting follow-up glucose assays, planning meals, maintaining good hydration during nonfasting periods, and prompt intervention when warning symptoms are detected. Shaltout et al. (2024)[21] also state that high-risk populations should be provided with individualized treatment plans, dose adjustments, and real-time patient support. Moreover, it is essential to dispel misconceptions, including the assumption that glucose testing ruins the fasting period, which can hinder effective monitoring and management. Even with moderate to high risks, patients can have safer fasting experiences with thorough, active, and culturally competent assistance. Finally, the simultaneous incorporation of education and clinical planning, with subsequent post-Ramadan assessment, into annual care pathways will help ensure the long-term maintenance of diabetes control and the related empowerment of patients facing the challenges of Ramadan fasting.

Conclusion

Ramadan fasting offers both benefits and risks for individuals with type 2 diabetes mellitus (T2DM). While fasting can improve insulin sensitivity, reduce inflammation, and support mental well-being, it may also increase the risk of hypoglycemia, dehydration, or ketoacidosis without proper care. Evidence supports using tools like the IDF-DAR risk model, pre-Ramadan assessments, and tailored education to ensure safe fasting. Studies from Saudi Arabia and Malaysia show that many patients can fast successfully with proper guidance. Annual reviews and individualized medical advice remain essential. With professional support, most individuals with T2DM can fast safely and gain physical and psychological benefits.

Limitations and Future Aspects

This narrative review has several limitations that should be acknowledged. First, as a nonsystematic review, it did not follow the rigorous search, selection, and appraisal processes used in systematic reviews or meta-analyses. The inclusion of studies was limited to publications available in English from 2021 onward, which may have excluded earlier or non-English evidence relevant to Ramadan fasting and type 2 diabetes. Second, most of the included studies were observational or cross-sectional in design, with relatively small sample sizes and short follow-up periods. These factors limit the ability to establish causal relationships or long-term outcomes. Third, variations in fasting duration, geographic region, climate, cultural dietary habits, and medication adherence among participants make it difficult to generalize findings across all Muslim populations. Finally, there remains a lack of data from large randomized controlled trials (RCTs) assessing the physiological, psychosocial, and metabolic consequences of Ramadan fasting in diverse diabetic populations.

Future research should focus on conducting large, multicenter, randomized controlled studies with standardized protocols to evaluate metabolic and clinical outcomes in patients with type 2 diabetes who fast during Ramadan. Longitudinal research is also needed to explore the long-term effects of repeated annual fasting on glycemic control, cardiovascular health, and renal function. Future investigations may also benefit from integrating continuous glucose monitoring, digital health interventions, and artificial-intelligence-based risk stratification tools to improve personalized fasting guidance. Additionally, studies evaluating the impact of structured pre-Ramadan education programs, telemedicine support, and culturally sensitive dietary counseling would contribute to safer and more effective fasting practices for diabetic patients.

Ethical consideration

This study was conducted digitally at Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh, Saudi Arabia. All research activities followed the ethics of the Declaration of Helsinki and the Uniform Requirement of Manuscripts Submitted to Biomedical Journals as advised by the International Committee of Medical Journal Editors (ICMJE). The data used to draw the results of this work are available in Excel and can be requested at the discretion of the corresponding author. Each author is aware of and agrees to the final version of the manuscript, which they have signed before its submission.

Highlights

• Ramadan fasting, one of the Five Pillars of Islam, has been observed for over 1,400 years.

• Muslims abstain from eating and drinking from sunrise to sunset, with most having two meals: Suhoor and Iftar.

• Exemptions for unwell, pregnant, breastfeeding, or traveling individuals.

• Fasting can alter energy, nutritional intake, food composition, working hours, and daily routine.

• It can cause metabolic and physiological alterations, including fluctuations in body weight and disruptions in the circadian cycle.

• Positive effects include improving gut flora, adjusting gut hormone levels, reducing body weight, and lowering pro-inflammatory indicators.

Abbrevations

BMI: Body mass index

T2DM: Type 2 diabetes mellitus

DKA: Diabetic ketoacidosis

DKD: Diabetic kidney disease

IDF-DAR: International Diabetes Federation and Diabetes and Ramadan International Alliance

HCPs: Healthcare providers

HHS: Hyperosmolar hyperglycemic state

WHO-5: The World Health Organization-Five Well-Being Index

TEE: Metabolic energy expenditure

T1DM: Type 1 diabetes mellitus.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.