Chhath Puja's 36-Hour Nirjala Fast: How to Prepare, Who Should Not, and How to Break It

The devotion is the point, and nothing here argues against it. The aim is to explain what 36 hours without water does to the body, who is at real risk, and how to prepare and break the fast so that the vratin reaches the ghat on the last morning steady on her feet.

What happens in the body during 36 hours without food or water?

The body shifts fuel within a day and slowly runs short of water throughout. For the first several hours it uses glucose from the last meal, then draws on glycogen stored in the liver, which is largely used up within about a day. After that it burns more fat and makes ketones, which is why some vratins feel headachy or light-headed on the third day. Water is the harder limit. The body keeps losing it through breath, skin and urine even when you drink nothing, and the kidneys can concentrate urine only so far. As water falls, blood volume drops slightly, the heart beats faster on standing, and dizziness, headache and poor concentration become likely.

Is the nirjala fast safe for a healthy adult?

For most healthy adults, yes, provided they prepare well and stop if warning signs appear. There are no clinical studies of Chhath itself, so the closest evidence comes from Ramadan, when many millions of people abstain from food and water during daylight. A 2003 review in the European Journal of Clinical Nutrition found significant metabolic changes but few health problems in healthy fasters; headaches, irritability and tiredness were common, and no harm could be directly attributed to the water deficit. That reassurance has a limit. A Ramadan day without water lasts roughly twelve to sixteen hours and ends with a night of drinking, while the Chhath fast runs continuously for about 36 hours, so the Chhath deficit is larger.

Who should not keep the nirjala fast?

Anyone for whom a day and a half without water could tip a medical condition into an emergency. That includes people with diabetes treated with insulin or sulfonylurea tablets, chronic kidney disease or a history of kidney stones, heart failure or significant heart disease, and people taking diuretics or several blood pressure medicines. Pregnant and breastfeeding women, frail or very elderly vratins, people with a tendency to faint or very low blood pressure, and anyone who has had diarrhoea, vomiting, dengue or fever in the preceding weeks are also at higher risk. So is anyone with a history of an eating disorder. For these groups, the conversation with a doctor should happen weeks ahead, not on the evening of Kharna.

Can a person with diabetes keep the Chhath fast?

Only after a specific plan made with their doctor, and many should not fast without water at all. The risk is not theoretical. The EPIDIAR study, which surveyed 12,243 people with diabetes across 13 countries during Ramadan, found that severe hypoglycaemia was far more frequent during the fasting month: 0.03 episodes a month against 0.004 in other months for type 2 diabetes, and 0.14 against 0.03 for type 1. The 2017 practical guidelines from the International Diabetes Federation and the DAR Alliance advise assessing risk well in advance and ending a fast at once if blood glucose drops below 70 mg/dL or rises above 300 mg/dL. Anyone on insulin or a sulfonylurea should have their doses reviewed by the prescribing doctor beforehand and never adjust them alone. More on festival fasts with diabetes is in fasting with diabetes.

Is the nirjala fast safe during pregnancy?

It has not been studied, and the safer course is not to fast without water while pregnant. The nearest evidence is again from Ramadan. A 2018 systematic review in BMC Pregnancy and Childbirth pooled 22 studies covering 31,374 pregnancies and found that daytime Ramadan fasting did not reduce birth weight or increase preterm birth, but the authors judged the evidence on other outcomes too thin to call the practice safe. A continuous 36-hour dry fast is a larger stress than daytime fasting, and dehydration in pregnancy can bring on contractions, dizziness and urinary infections. A pregnant woman who wishes to observe Chhath should discuss it with her obstetrician. The rituals, the songs and the arghya at the ghat do not depend on going without water, and families can decide together how she takes part.

Why are older vratins at greater risk?

Because the ageing body senses thirst less, conserves water less efficiently, and is more likely to be on medicines that complicate a dry fast. A 2015 review in Nutrition Reviews linked dehydration with urinary, circulatory and neurological problems, while noting that much of the evidence is associative rather than drawn from trials. A separate review of hydration and the brain, published in 2014, pointed out that older people and children regulate fluid less well and are more vulnerable to the effects of dehydration on mood and thinking. In practice that means confusion, a fall on wet ghat steps, or a faint while standing in cold water at dawn. Grandmothers who have kept Chhath for forty years may be fitter than most, but age changes the arithmetic even for them.

How should you prepare in the week before Chhath?

Prepare the body the way you prepare the house: steadily, not at the last minute. See your doctor if you have any condition or take regular medicines. If you drink several cups of tea or coffee a day, cut down gradually over three to four days before Nahay Khay, because caffeine withdrawal during the fast is a common and avoidable cause of headache. Drink normally through the week and eat regular, balanced meals with enough protein and vegetables, so you begin the fast well nourished. Try to sleep properly in the days before, since the night between the evening and morning arghya often goes without rest. Arrange for others to carry the heavy baskets and do the long standing work.

Making Nahay Khay and Kharna work for the fast

The traditional meals are well suited to the fast if they are eaten in reasonable quantity. Nahay Khay's lauki cooked with chana dal, served with rice and a little ghee, is easy to digest and gives protein, carbohydrate and water. The Kharna offering of rasiya, rice cooked in milk with jaggery, eaten with roti or puri, is the last food before the nirjala period, and its milk adds fluid and protein. Within whatever the family's custom allows, eat a proper plate at Kharna rather than a token mouthful, and include the dal or vegetable if one is served. Very salty or heavily fried food at this point increases thirst later, so the fried prasad is better saved for after the fast.

How much water should you drink before the fast begins?

Drink steadily through the day and evening before, aiming for pale yellow urine, rather than forcing a large volume at the last moment. There is no single correct number, because needs depend on body size, weather and how much work you are doing; the water intake calculator gives a reasonable everyday baseline. The common habit of drinking two litres in the final hour before the fast is not helpful: the kidneys excrete excess water within a few hours, so most of it is lost before the night is out, and it can cause nausea. Spreading fluid across the day, with water-rich foods such as lauki, milk and fruit where custom allows, keeps more of it in the body.

Staying safe at the ghat

Most emergencies at the ghat come from heat of the crowd, standing too long, slippery steps and cold, not from the fast alone. Sit down whenever the ritual allows, and let a younger family member accompany any elderly vratin into and out of the water. Stand in the water only as long as the arghya requires. Wear or carry warm layers for the pre-dawn offering, and change into dry clothes as soon as possible afterwards, because shivering burns energy the fasting body can ill afford. Avoid the most crowded, pushing sections of the ghat. Families should know the nearest hospital and keep a charged phone, and someone should be watching the vratin rather than the fireworks.

Which warning signs mean the fast should stop?

Confusion, fainting, chest pain or a racing heartbeat, repeated vomiting, severe cramps, uncontrollable shivering or passing very little urine mean the fast must end and medical help must be sought. For anyone with diabetes, a glucose reading below 70 mg/dL or above 300 mg/dL, or symptoms of a low such as sweating, trembling and confusion, means the same. Mild hunger, a dull headache and tiredness are expected on the third day; the signs above are not. Families sometimes hesitate because breaking the vrat feels like failure, and a vratin may insist on continuing. It is worth agreeing beforehand, calmly and with the vratin herself, that her safety comes first and that the family will act if these signs appear.

How should you break the Chhath fast?

Slowly, starting with fluid, then light food, then a proper meal a couple of hours later. After the morning arghya, begin with small sips of water over the first 30 minutes, followed by a glass of oral rehydration solution, nimbu-pani with a pinch of salt and sugar, or coconut water, which replace salts as well as water. Then take something soft from the prasad, such as a ripe banana or a little of the fruit, and a small piece of thekua if you wish. Within one to two hours, eat a simple cooked meal such as dal and rice or khichdi. Eating a heap of fried prasad on an empty, dry stomach is a reliable route to vomiting and a headache. The next day, sattu drink is a traditional and filling choice.

How many calories are in a thekua?

Roughly 100 to 180 kcal per piece, depending on its size and how much ghee it absorbs during frying. Thekua is made from wheat flour, jaggery or sugar and ghee, shaped in a wooden mould and deep fried, so it is dense in energy and sugar. The prasad is shared with neighbours and eaten for days afterwards, and three or four pieces a day soon add up. Jaggery is often described as a healthier sweetener, but the body handles it much like sugar, as jaggery, honey or sugar explains. People with diabetes can enjoy a piece of prasad as part of a meal rather than on its own, and should keep an eye on their readings in the days after the festival.

Teaching families to fast with care

Most of the risk in a festival fast is predictable: the grandmother on blood pressure tablets, the daughter-in-law in her first trimester, the uncle on insulin, the rush of fried food at parana. Spotting these situations early and giving clear, respectful advice does not need a clinical degree, but it does need a grounding in everyday nutrition and hydration. NNWA's Healthy Eating and Everyday Wellness course is a three-week beginner course in family-friendly Indian eating habits, taught in English and Hindi with mentor support, at Rs 3,499. Dr Sucharita Sengupta, who holds an MSc in Food Science and Nutrition and a PG Certificate in Diabetes Education, reviewed this guide. To see how NNWA teaches before enrolling, the free webinars are open to anyone.

The short version for vratins and families

Chhath's nirjala fast is manageable for healthy adults who prepare. Reduce tea and coffee over three to four days, sleep well, eat a proper Kharna meal, and drink steadily through the day before rather than in one rush. Let others do the heavy work, sit when you can, and stay warm and dry at the dawn arghya. Break the fast with sips of water, then oral rehydration solution, nimbu-pani or coconut water, then soft food, then a simple meal. People with diabetes on insulin or sulfonylureas, kidney or heart disease, pregnancy, frailty or a recent illness need a doctor's advice first. Stop at once for confusion, fainting, chest pain or very little urine.

Research this article draws on

Leiper et al. (2003). Effects on health of fluid restriction during fasting in Ramadan. European Journal of Clinical Nutrition. Reviewed studies of daylight food and fluid restriction: metabolic changes were common but health problems few; headaches, irritability and reduced medicine adherence were the main downsides, and no harm was directly attributed to the water deficit.

Salti et al. (2004). A Population-Based Study of Diabetes and Its Characteristics During the Fasting Month of Ramadan in 13 Countries. Diabetes Care. Among 12,243 people with diabetes, severe hypoglycaemia was markedly more frequent during the fasting month than in other months, especially when medicine doses or activity changed.

Hassanein et al. (2017). Diabetes and Ramadan: Practical guidelines. Diabetes Research and Clinical Practice. IDF and DAR International Alliance guidance on risk stratification, nutrition and medicine adjustment for people with diabetes who fast, including when a fast should be broken.

Glazier et al. (2018). The effect of Ramadan fasting during pregnancy on perinatal outcomes: a systematic review and meta-analysis. BMC Pregnancy and Childbirth. Across 22 studies and 31,374 pregnancies, daytime fasting did not affect birth weight or preterm birth, but evidence on other outcomes was too limited to establish safety.

El-Sharkawy et al. (2015). Acute and chronic effects of hydration status on health. Nutrition Reviews. Linked dehydration with urological, gastrointestinal, circulatory and neurological disorders, while cautioning that much of the evidence is associative and randomised trials are few.

Masento et al. (2014). Effects of hydration status on cognitive performance and mood. British Journal of Nutrition. Reviewed behavioural and imaging studies showing dehydration affects aspects of mood and thinking, with older people and children most vulnerable because they regulate fluid less well.