What will happen if you do Monday fasting? A look at benefits, traditions, and risks

December 8, 2025 •

3 min read

With centuries of practice across different cultures, intermittent fasting has gained modern wellness attention, and Monday fasting, or Somvar Vrat, is a prime example. This tradition involves more than just religious devotion, with potential physical and mental benefits that have captured scientific interest.

Quick Summary

This article explores the spiritual significance, scientific health benefits, and potential risks of Monday fasting, offering a balanced perspective on this weekly ritual. It covers traditions, metabolic effects, and practical guidance.

Key Points

Spiritual Significance: Monday fasting, or Somvar Vrat, is a devotional practice in Hinduism dedicated to Lord Shiva for blessings and prosperity.
Spiritual Reward in Islam: Muslims fast on Mondays and Thursdays, following a sunnah of the Prophet Muhammad, as deeds are believed to be presented to Allah on these days.
Metabolic Switch: Weekly fasting can trigger metabolic switching, where the body shifts from burning sugar to stored fat for energy, aiding weight loss and boosting metabolism.
Enhanced Insulin Sensitivity: Intermittent fasting can improve insulin resistance, helping to regulate blood sugar levels and potentially lowering the risk of type 2 diabetes.
Mental and Emotional Benefits: Fasting can lead to improved mental clarity, concentration, and emotional stability by stimulating neurotrophic factors and encouraging self-discipline.
Risks and Precautions: Potential risks include dehydration, nutrient deficiencies, fatigue, and mood swings. Individuals with underlying health conditions, pregnant women, and the elderly should consult a doctor before fasting.

Understanding the Traditions of Monday Fasting

Fasting on Mondays is a practice with deep spiritual and cultural roots, observed for centuries by many different communities around the world. The reasons for this tradition are diverse, often combining spiritual devotion with personal discipline. By understanding the historical and religious context, one can better appreciate the holistic nature of Monday fasting.

Monday Fasting in Hinduism: Somvar Vrat

In Hinduism, the Monday fast, known as Somvar Vrat, is primarily dedicated to Lord Shiva. Mondays are considered particularly sacred for Shiva worship, and observing a fast is believed to bring peace, prosperity, and the fulfillment of wishes. During Somvar Vrat, devotees typically wake early, bathe, and offer prayers and rituals to Lord Shiva, potentially including Abhishekam. Dietary restrictions vary, sometimes involving complete abstinence or limiting intake to fruits and milk, and the fast is usually broken after sunset with a light meal. This fast is observed by many, including unmarried women seeking a good spouse and married women for marital happiness.

Monday Fasting in Islam

Many Muslims observe fasting on Mondays and Thursdays as a sunnah (practice) of the Prophet Muhammad (PBUH). This is because it is believed that actions are presented to Allah on these days. This practice fosters spiritual reflection, strengthens taqwa (consciousness of Allah), and promotes self-discipline and empathy.

The Scientific Effects of Weekly Fasting

Beyond spiritual reasons, weekly fasting offers scientifically observed health benefits associated with intermittent fasting. While not all who fast weekly do so for health, the physiological effects are similar.

Metabolic and Cardiovascular Improvements

Fasting for 12-24 hours can lead to metabolic switching, where the body burns fat for energy after depleting sugar stores. This can result in:

Weight Loss: Reduced calorie intake and fat burning, particularly around the belly.
Improved Insulin Sensitivity: Better insulin use helps manage blood sugar and may lower type 2 diabetes risk.
Better Heart Health: Potential reduction in blood pressure, cholesterol, and triglycerides.

Mental Clarity and Cognitive Function

Fasting can impact brain health, though research continues. Benefits may include:

Enhanced Brain Function: Using ketones for fuel can stimulate BDNF, potentially improving cognitive function and memory.
Increased Focus: Many report improved concentration during fasting.
Reduced Inflammation: Lower inflammatory markers may protect against neurodegenerative diseases.

Comparison of Fasting Practices


Feature	Somvar Vrat (Hindu)	Monday & Thursday Fast (Islam)	Intermittent Fasting (16:8)
Purpose	Devotion to Lord Shiva, seeking blessings	Emulating Prophet Muhammad, spiritual rewards	Weight loss, metabolic health
Day(s)	Monday	Monday and Thursday	Any regular schedule
Restrictions	Varies; often Nirjala (no water) or Phalahar (fruits, milk)	Abstaining from food/drink from dawn to sunset	Eating within an 8-hour window
Flexibility	Rules are tied to spiritual devotion	Set days with clear rules	Time-based, adaptable to personal schedule
End of Fast	After evening prayers and moon sighting	At sunset with an iftar meal	After the designated fasting period ends

Risks, Precautions, and Best Practices

Fasting can be beneficial but also carries risks and isn't suitable for everyone.

Potential Risks

Dehydration: Especially with dry fasting.
Nutrient Deficiencies: With improper planning.
Fatigue and Irritability: Common during initial adjustment.

Who Should Avoid Fasting?

Consult a healthcare professional if you are:

Pregnant or breastfeeding.
Have diabetes or other medical conditions.
Have a history of eating disorders.
Are underweight.

Tips for Safe and Successful Fasting

For those who fast, consider these tips:

Start Gradually: Begin with shorter or less strict fasts.
Stay Hydrated: Drink plenty of water during non-eating times.
Eat Nutrient-Dense Foods: Focus on whole foods during eating periods.
Listen to Your Body: Break the fast if you feel unwell.
Limit Strenuous Activity: Reduce intense exercise on fast days.

Conclusion: A Holistic View on Monday Fasting

What happens when you fast on Mondays depends on individual goals and health. It can be a spiritual practice for discipline and divine connection, or a health strategy for weight management and metabolic benefits. The practice promotes mindfulness. Always approach fasting cautiously, listen to your body, and consult a healthcare professional, especially with existing health conditions, to ensure it is both meaningful and safe.

For more detailed information on intermittent fasting and its effects, consider reading resources from Johns Hopkins Medicine: Intermittent Fasting: What is it, and how does it work?.

Frequently Asked Questions

In Hinduism, the Monday fast (Somvar Vrat) is primarily observed to honor Lord Shiva, seeking his blessings for prosperity, peace, and the fulfillment of wishes. In Islam, fasting on Mondays and Thursdays is a sunnah practice, rooted in the belief that deeds are presented to Allah on these days.

Yes, as a form of intermittent fasting, regular Monday fasting can aid in weight loss by reducing overall calorie intake and promoting metabolic switching, where your body starts burning fat for energy.

During a weekly fast, your body enters a state of metabolic switching after exhausting its glucose stores. It begins converting stored fat into energy through the production of ketone bodies, which can improve insulin sensitivity and boost metabolism.

Certain groups of people should avoid fasting or do so only under medical supervision. These include pregnant or breastfeeding women, individuals with diabetes, those with a history of eating disorders, and people with a low body weight.

Yes, especially during the initial adjustment phase, side effects can include headaches, lethargy, irritability, mood swings, and dehydration. Staying well-hydrated and listening to your body are crucial for managing these effects.

When breaking a fast, especially a longer one, it is recommended to reintroduce food slowly to prevent digestive issues. Opt for light, nutrient-dense foods like fruits or a simple meal, and avoid overeating or consuming processed foods immediately.

Some studies suggest that fasting can have a positive impact on brain function and mental clarity by stimulating the production of brain-derived neurotrophic factor (BDNF). Many individuals report feeling more focused and experiencing less mental fog during fasting periods.