INTRODUCTION:

Fasting, the deliberate abstention from food and drink, has been a significant practice across various cultures and religions for centuries.¹ Its origins are deeply rooted in ancient civilizations, from Mesopotamia and Egypt to Greece, India, and China. In modern times, fasting has gained renewed attention due to its potential health benefits and spiritual significance.

A Surveys indicate that approximately 25% of adults in the United States have experimented with intermittent fasting, reflecting its growing popularity.² Similarly, a study in the United Kingdom found that around 20% of people engage in some form of fasting for health reasons³. In Australia, nearly 30% of adults have reported trying intermittent fasting as part of their diet. Approximately 15-20% of Japanese adults are estimated to engage in some form of fasting, including intermittent fasting for health purposes.⁴ Fasting is deeply embedded in Indian culture and religion, with significant participation among Hindus, Jains, and Buddhists. For instance, it's estimated that around 60-70% of Hindus in India regularly observe fasting during religious events such as Navratri and Ekadashi. Jainism also incorporates rigorous fasting practices, with approximately 10% of Jains observing fasts like Paryushana and Santhara.⁵

Despite the extensive research on fasting, several gaps remain in our understanding. Many reviews focus predominantly on the physiological and metabolic impacts of fasting, often overlooking its rich historical, cultural, and spiritual dimensions. Moreover, while there is a considerable amount of research on intermittent fasting and its health benefits, there is less comprehensive analysis on the comparative effectiveness of different fasting methods, such as dry fasting, juice fasting, and partial fasting. Another significant gap is the lack of region-specific data, particularly in Asian countries, where fasting practices are deeply rooted in cultural and religious traditions. Additionally, much of the existing literature tends to generalize findings without adequately considering individual differences, such as age, gender, and pre-existing health conditions.

This review aims to fill these gaps by providing a comprehensive overview of fasting, examining its history, cultural and religious significance, various types, and the evidence-based health effects. Additionally, it addresses common myths and beliefs, separating fact from fiction, making it a unique and comprehensive resource for understanding the multifaceted nature of fasting.

HISTORICAL SIGNIFICANCE:

Fasting, the voluntary abstention from food and drink, has deep historical roots across numerous ancient civilizations. Its origins are difficult to pinpoint, as it evolved independently in various societies. In ancient Mesopotamia (3000 BCE), Sumerians practiced fasting for spiritual purification and religious rituals linked to lunar phases. Ancient Egyptians believed fasting cleansed the body and soul for communion with gods, as evidenced by hieroglyphics and medical texts like the "Ebers Papyrus" (1550 BCE). Greek philosophers such as Pythagoras and Socrates from around 600 BCE document fasting practices for mental clarity, spiritual growth, health benefits and enlightenment, with Hippocrates recommending it for healing¹. In India, fasting is integral to Hinduism, Jainism, and Buddhism for spiritual growth, with texts like the "Upanishads" and "Bhagavad Gita" dating back to 1000 BCE emphasizing its importance, Jainism incorporates rigorous fasting to purify the soul, while Buddhism practices moderate fasting for self-discipline. In ancient China, dating back to 400 BCE influenced by Daoist and Confucian philosophies, fasting was believed to harmonize the body with the cosmos and promote health, as seen in Daoist texts and Traditional Chinese Medicine.⁶ Fasting has been used as a form of protest and solidarity, exemplified by Mahatma Gandhi’s fasting against violence and social injustices, and other figures like Dick Gregory and Irish nationalists, who used hunger strikes to protest political and social issues.¹ Determining which civilization first practiced fasting is challenging due to the overlapping timelines and geographical dispersion of early human societies. However, the evidence suggests that fasting emerged independently across various cultures, each attributing different meanings and purposes to the practice.

CULTURAL AND RELIGIOUS CONTEXT:

Fasting, known as "Vrata" in Hinduism, is a revered practice undertaken for spiritual reasons, atoning for sins, seeking blessings, or achieving discipline. Key fasts include "Ekadashi" and "Navratri," during which adherents abstain from grains and meat, consuming fruits, dairy, and simple vegetarian meals. In Jainism, fasting is crucial for spiritual purification and non-violence (Ahimsa), with the most rigorous form being "Santhara" or "Sallekhana," an end-of-life fast. Regular practices include "Paryushana," an annual eight-day fast involving intense spiritual practices and seeking forgiveness. Buddhism uses fasting to cultivate self-discipline and mental clarity, where monks and nuns abstain from solid food after noon, and lay Buddhists observe fasting on "Uposatha" days, coinciding with lunar phases, focusing on meditation, ethical observance, and teachings. In Islam, fasting, or "Sawm," is a pillar of the faith, most notably observed during Ramadan. Muslims fast from dawn to sunset, promoting spiritual renewal, self-discipline, and empathy, breaking the fast with "Iftar" after sunset. Ramadan also includes increased prayer, reflection, and community involvement. Christianity's fasting practices vary across denominations, with Catholics fasting during Lent, abstaining from meat on Fridays, while Orthodox Christians have stringent fasts during Lent. Protestant practices focus on penance, reflection, and solidarity with Jesus Christ. In Judaism, fasting is significant, especially on Yom Kippur, a 25-hour fast for repentance and spiritual purification, and other fasts like Tisha B'Av and minor fasts like the Fast of Esther focus on reflection, prayer, and repentance. Fasting is observed from sunrise to sunset during the Baha’I month of ‘Ala with the complete abstention of food and drink. Patients are permitted to take medications while fasting.⁶ Indigenous practices include Native American vision quests involving fasting for spiritual guidance, and Australian Aboriginal cultures use fasting in rites of passage to connect with the spiritual realm. Modern secular practices, such as intermittent fasting, are popular for health benefits like weight loss and metabolic improvement, reflecting a growing recognition of the potential benefits of controlled food intake.⁷

TYPES OF FASTING:

Fasting has evolved into various forms as discussed here, each with distinct purposes and practices. It's essential to choose a fasting method that aligns with one's goals and health status, often after consulting with a healthcare provider.

· Intermittent fasting (IF): It involves cycling between periods of eating and fasting, with several common methods. The 16/8 Method entails fasting for 16 hours each day and eating within an 8-hour window. The 5:2 Diet involves eating normally for five days of the week and restricting calorie intake to 500-600 on two non-consecutive days. Another approach, known as Eat-Stop-Eat, requires fasting for 24 hours once or twice a week. Each method offers a structured way to manage eating patterns and potentially support various health benefits.^{2, 3}

· Time-Restricted Eating (TRF): Similar to intermittent fasting, this method restricts eating to specific times of the day, such as only eating between 10 AM and 6 PM.⁸ Research suggesting that eating within an eight-hour window or less was significantly associated with a 91% increased risk of dying from cardiovascular disease, when compared with eating over a 12- to 16-hour period. Another RCT revealed that that both TRE and a more traditional daily eating pattern resulted in weight loss when calories were held constant in both groups.⁹

· Periodic Fasting: This involves fasting for several days in a row, such as a 3-day or 5-day fast, and then eating normally for a set period.

· Alternate-Day Fasting: Individuals alternate between days of normal eating and days of fasting or eating very little (e.g., 500 calories).

· Prolonged Fasting: Extended fasting periods, typically ranging from several days to weeks, often undertaken for health or spiritual reasons. Medical supervision is recommended for fasts longer than 24 hours.¹⁰

· Dry Fasting: Dry fasting involves complete abstinence from all food and liquids and is divided into two types: hard dry fast, where there is no contact with water including bathing, and soft dry fast, which avoids drinking but allows minimal contact with water.¹¹

· Juice Fasting: Consumption of only fruit and vegetable juices while abstaining from solid foods. Often used for detoxification and weight loss.

· Partial Fasting: Partial fasting involves restricting specific types of food or meals rather than abstaining from all food. For example, the Daniel Fast, a practice in Christianity, entails consuming only fruits, vegetables, and water. Similarly, the Macrobiotic Diet is a semi-fast that emphasizes whole grains and vegetables, while avoiding processed foods. Both approaches aim to promote health and spiritual well-being through selective dietary choices.¹²

· Therapeutic Fasting: Fasting, when done under medical supervision, can be used to address specific health conditions such as obesity, diabetes, and autoimmune diseases. Some fasting approaches, especially those for treating chronic conditions, may extend beyond a month and permit only the consumption of water or calorie-free tea, often incorporating exercise and enemas. Other approaches, known as modified fasting, involve a daily intake of 200 to 800 kilocalories and may also include psychological or spiritual therapy. These calories usually come from sources like bread, vegetable broth, fruit juice, honey, or milk.¹³

· Religious fasting: Carried out by various religions for various reasons.⁷

HEALTH BENEFITS OF FASTING:

Fasting is often promoted for its potential to aid weight loss¹⁴ and improve metabolic health. Research suggests that intermittent fasting can facilitate weight loss by reducing calorie intake and increasing metabolic rate. Studies have shown that fasting can enhance insulin sensitivity, lower insulin and glucose levels, and reduce the risk of type 2 diabetes.² Additionally, fasting is linked to cellular repair processes, including autophagy, where cells eliminate damaged components. This process is believed to contribute to increased longevity, and some studies suggest that fasting can lower inflammation markers, potentially reducing the risk of chronic diseases.¹⁵ While animal studies have demonstrated that fasting can extend lifespan, more research is needed in humans. Fasting may also benefit cardiovascular health by reducing blood pressure, cholesterol levels, and triglycerides, and by decreasing markers of inflammation.³ Fasting can help improve gut health by allowing the digestive system to rest and repair. This can lead to better digestion, reduced inflammation, and a healthier gut microbiome.¹⁶ Furthermore, there is growing evidence that fasting can support mental health and cognitive function by increasing the production of brain-derived neurotrophic factor (BDNF), a protein that supports neuron growth and brain function. Some studies indicate that fasting can improve mood and cognitive performance.¹⁷ While the existing evidence is promising, more research is needed to fully understand the long-term effects of fasting on various aspects of health, particularly in diverse populations and different age groups.

MYTHS AND MISCONCEPTIONS ABOUT FASTING:

Fasting is often surrounded by myths and misconceptions that can lead to misunderstandings about its effects and practices. Some common myths include:^{18, 19}

· Myth 1: Fasting Leads to Muscle Loss: A common belief is that fasting causes significant muscle loss. However, research indicates that short-term fasting primarily affects fat stores rather than muscle tissue. Adequate protein intake and resistance training can help preserve muscle mass during fasting periods.

· Myth 2: Fasting Slows Down Metabolism: Contrary to the belief that fasting slows metabolism, studies show that intermittent fasting can actually boost metabolic rate by increasing norepinephrine levels, which helps in fat burning.. Extended fasting can eventually slow metabolism as the body adapts to conserve energy, but intermittent fasting typically does not have this effect.

· Myth 3: Fasting Causes Nutrient Deficiencies: While prolonged fasting can lead to nutrient deficiencies, intermittent fasting, when done correctly, allows for adequate nutrient intake during eating periods. Ensuring a balanced diet with nutrient-dense foods during eating windows can prevent deficiencies.

· Myth 4: Fasting Is Unhealthy for Women: There is a belief that fasting is particularly harmful to women, especially regarding reproductive health. While some women may experience disruptions in their menstrual cycle due to extreme fasting, moderate and well-planned fasting can be safe. Women should pay attention to their body's responses and consult healthcare professionals before starting a fasting regimen.

· Myth 5: Fasting Is Only for Weight Loss: Fasting is often associated solely with weight loss, but its benefits extend beyond this. Fasting can improve metabolic health, enhance cellular repair processes, and support mental well-being, making it a holistic approach to health.

· Myth 6: Fasting is Just a Trend: Some people believe fasting is merely a passing trend without scientific backing. In truth, numerous studies support various health benefits of fasting, including weight loss, improved metabolic health, and enhanced cellular repair.

· Myth 7: One Can Eat Anything During Eating Windows: Some believe that fasting allows for unrestricted eating during eating windows. However, for optimal health benefits, it's important to focus on a balanced diet rich in nutrients rather than consuming excessive unhealthy foods.

· Myth-8: One Need to Fast for Long Periods to See Benefits: Another myth is that only prolonged fasting provides benefits. Shorter fasting periods, such as 16/8 or even shorter durations, can also offer significant health advantages.

SAFETY AND PRECAUTIONS:

Fasting can generally be safe for healthy individuals, but certain groups should exercise caution or avoid fasting altogether. Women who keep more fasts are likely to be more religious. However, such benefits may be neutralized as a result of added problem of fasting such as medical problem occurring on the day of fasting and observing fasts during vulnerable phases (pregnancy, lactation and adolescent.²⁰ Pregnant or breastfeeding women may be adversely affected by fasting, as it can impact the intake of essential nutrients needed for fetal and infant development, making it usually not recommended for these individuals.²¹ Children and adolescents require consistent and balanced nutrition to support their growth and development, which makes fasting generally unsuitable for them. Individuals with a history of eating disorders should approach fasting with caution or avoid it altogether, as it can potentially exacerbate disordered eating behaviors.²² Additionally, people with chronic conditions such as diabetes, heart disease, or other health issues should consult with healthcare providers before starting a fasting regimen to ensure it is safe and appropriate for their specific situation.²³

KEY RECOMMENDATIONS AND GUIDELINES;

Choosing the right fasting method involves understanding various approaches, such as intermittent fasting (e.g., 16/8, 5:2), alternate-day fasting, or prolonged fasting, and selecting one that aligns with individual lifestyle and health goals. Beginners should start with shorter fasting periods or less restrictive methods to allow the body to adjust. Maintaining balanced nutrition is essential; during eating windows, focus on consuming whole foods rich in essential nutrients, including fruits, vegetables, whole grains, lean proteins, and healthy fats. Adequate hydration should be ensured by drinking plenty of water throughout the fasting period, with herbal teas and black coffee being acceptable depending on the fasting method. Monitoring health is crucial: paying attention to how the body responds to fasting is important, and if any adverse symptoms like dizziness or fatigue occur, adjusting the fasting schedule or consulting a healthcare provider may be necessary. Regular check-ups with a healthcare provider are important for those with pre-existing health conditions or who are on medication to monitor any potential impacts of fasting. Planning meals wisely involves timing them appropriately and ensuring they include a mix of protein, fiber, and healthy fats to sustain energy levels and reduce hunger. Avoiding overeating during eating periods by practicing mindful eating and portion control helps to maintain the benefits of fasting. Incorporating regular physical activity supports metabolic health and weight management, but adjustments should be made based on energy levels. Managing stress through activities such as meditation, deep breathing, or yoga can also enhance the effectiveness of fasting. Special populations, including pregnant or nursing women and individuals with medical conditions like diabetes or eating disorders, should seek medical advice before starting fasting. Staying informed about the latest research and being flexible with the fasting approach based on personal experience and changing health or lifestyle demands is essential for a successful fasting practice.^19-25

CONCLUSION:

Fasting is a practice with deep historical, cultural, and religious roots, offering a range of health benefits supported by scientific evidence. While it is surrounded by numerous myths and misconceptions, understanding the facts about fasting can help individuals make informed decisions about incorporating it into their health routines. With proper guidance and attention to individual needs, fasting can be a safe and effective approach to improving overall health and well-being. Future research will continue to elucidate the long-term effects and optimal practices of fasting, helping to refine guidelines and recommendations for diverse populations. As our understanding of fasting evolves, it is essential to remain open to new evidence and adapt practices to ensure they are beneficial and sustainable.

CONFLICT OF INTEREST :

The authors declare no conflict of interest.

ACKNOWLEDGEMENT:

Supportive system of AIIMS Bibinagar

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Received on 15.01.2025 Revised on 13.05.2025

Accepted on 18.08.2025 Published on 21.02.2026

Available online from February 23, 2026

Asian J. Nursing Education and Research. 2026;16(1):61-65.

DOI: 10.52711/2349-2996.2026.00013