Fasting: doing it without harm

Fasting is practised by most of India in some form, Navratri, Ekadashi, Karva Chauth, Mahashivratri, Ramzan, Jain fasts, Monday and Tuesday vrats. It is woven into the calendar and into family life, and for most healthy adults it is unremarkable.

For some people it is genuinely risky, and the risk is rarely discussed because fasting is a religious practice rather than a dietary choice, and health advice feels like interference.

This article takes it as given that people will fast, and is about doing it without harm.

This is information, not medical advice. If you take medication, particularly for diabetes, speak to your doctor before fasting. Many doses need adjusting, and some people are advised not to fast at all.

Who should be careful, and who should not fast

Speak to a doctor first, this is not optional:

Diabetes on insulin or sulfonylureas (glimepiride, glibenclamide, gliclazide). These drugs lower blood sugar whether or not you have eaten, so a fast can cause hypoglycaemia, which can be severe. Doses almost always need adjusting, and the adjustment is a medical decision.

Metformin alone carries much less hypoglycaemia risk, but a conversation is still sensible.

Type 1 diabetes, fasting carries significant risk and needs specialist guidance.

Chronic kidney disease, fluid and electrolyte balance matters, and fluid restriction may be needed rather than encouraged.

Heart failure or on diuretics, fluid shifts are the concern.

On blood pressure medication, dehydration plus antihypertensives can drop blood pressure enough to cause fainting.

Pregnancy and breastfeeding. Many religious traditions provide explicit exemptions, and they exist for good reason. Fetal growth and milk supply both depend on steady nutrition.

On thyroid medication, it needs an empty stomach, and timing changes during a fast.

On lithium, or on medicines needing stable blood levels.

History of eating disorder. Fasting can reactivate a pattern, and this deserves care rather than dismissal.

Should generally not fast:

• Acute illness, fever or infection
• Recent surgery
• Active peptic ulcer
• Significant anaemia
• Underweight, or recent unintentional weight loss
• Uncontrolled diabetes
• Children, elderly people who are frail, and anyone with dementia
• During chemotherapy or active cancer treatment, unless the oncologist agrees

Most religious traditions permit exemption on medical grounds. If your doctor advises against it, that is a legitimate basis for not fasting, and most families and religious authorities accept it. People often do not realise this.

The problem nobody expects: the vrat food itself

Here is the finding that surprises people most. For many who fast in India, the fast is not the health problem, the vrat diet is.

Look at what a typical Navratri or Ekadashi plate contains: sabudana khichdi, sabudana vada, aloo, kuttu or singhara puri, fried snacks, and plenty of sweets.

Sabudana (tapioca) is almost pure starch, very high glycaemic, with negligible protein. Aloo likewise. Fried kuttu puri adds a large fat load. And then there are the mithai.

So the day looks like this: no food for several hours, then a large, high-glycaemic, deep-fried, low-protein meal. That is a worse pattern for blood sugar than an ordinary day of normal meals, and for people with diabetes or prediabetes it is a genuinely poor combination.

Add in the frequent absence of vegetables, and a fast that is meant to be purifying can be nutritionally worse than not fasting.

This is correctable without compromising the fast at all, which is the useful part. The traditions specify which foods are permitted; they do not specify that those foods must be fried.

Making the vrat plate better

Working within what is typically allowed:

Add protein, which is the biggest gap:

• Dahi and paneer, permitted in most vrats and the single most useful addition
• Milk
• Nuts and seeds, almonds, walnuts, peanuts, melon seeds
• Makhana, roasted rather than fried
• Rajgira (amaranth), notably better than sabudana, with real protein

Add vegetables. Most vrats permit pumpkin, bottle gourd, cucumber, tomato, spinach, carrot. A sabzi alongside changes the meal’s whole profile.

Choose better carbohydrates. Rajgira and kuttu are better than sabudana. Sweet potato is better than potato.

Change the cooking. Roast or steam rather than deep-fry. Roasted makhana instead of fried; a rajgira roti instead of a puri; steamed rather than fried sabudana.

Use fruit for sweetness instead of mithai.

One honest note: rock salt (sendha namak) is used instead of regular salt in many vrats. It is not nutritionally superior, the swap is a ritual distinction, not a health one. Both are largely sodium chloride.

Water, and the two kinds of fast

If your fast permits water, drink it. Generously. This is the most important single piece of advice here, and most Indian fasts do permit water.

If it does not, nirjala vrats, and fasts in some traditions, the considerations change:

• Hydrate well the night before and in the morning before starting
• Avoid heat and sun exposure, and avoid exertion
• Avoid heavy exercise entirely
• Shorten the fast if you develop symptoms, this is not failure
• High-risk groups should not undertake waterless fasts, and this is where most fasting-related emergencies come from
• Summer waterless fasting is considerably riskier than winter

Warning signs of dehydration: very dark or absent urine, dizziness on standing, headache, dry mouth, rapid heartbeat, confusion. Confusion or fainting means stop and get help.

Breaking the fast

This matters more than people think, and the traditional way is usually right.

The traditional pattern, fruit, dates, water, something light, is sound. Problems arise with the modern version: breaking a fast with a heavy fried meal.

Why it causes trouble: the stomach has been empty for hours, and a sudden large, fatty load produces reflux, bloating, pain and sometimes vomiting. In people with gallstones, a sudden large fat load can precipitate a gallbladder attack.

Better sequence:

1. Water first, a glass or two
2. Something light, fruit, dates, a little curd
3. Wait twenty or thirty minutes
4. Then a normal-sized meal, not a feast
5. Protein with it

And eat slowly. The fast ends when you break it, not when you finish the plate.

Specific medication issues

Worth spelling out, because these are the practical traps.

Diabetes medication, timing and dose both change. Do not simply skip a dose or take it as usual. Ask your doctor. People with diabetes who fast should also monitor sugar more frequently, and checking blood glucose does not break a fast in the view of most religious authorities.

Know hypoglycaemia symptoms: sweating, trembling, palpitations, sudden hunger, confusion, irritability. If they occur, break the fast immediately and take sugar. Every tradition permits breaking a fast to prevent harm.

Thyroid medicine needs an empty stomach, so it fits a fast well, take it early, and keep calcium and iron four hours away.

Medicines usually taken with food, metformin, NSAIDs, some antibiotics, can cause gastric upset on an empty stomach. Ask about rescheduling.

Blood pressure medicines plus dehydration can cause fainting. Stand up slowly.

Blood thinners need consistent conditions; tell your doctor.

Caffeine withdrawal is a common and underestimated cause of fasting headache in people who normally drink several teas a day. Tapering caffeine a few days before helps considerably.

What about the health claims made for fasting?

Since intermittent fasting is heavily marketed, a brief honest word.

There is genuine research interest in time-restricted eating and intermittent fasting, with studies on weight, insulin sensitivity and metabolic markers. Some results are promising.

What the evidence does not support: that fasting “detoxifies” the body, “resets” the liver or the gut, or removes accumulated toxins. Those claims are not what the research says, and we have written separately on why the detox framing does not survive contact with the biology.

And one thing worth saying plainly: the metabolic benefits studied in intermittent fasting trials come from restricting the eating window while eating sensibly within it. A fast followed by fried sabudana and mithai is not the intervention those studies tested.

Religious fasting is also not primarily a health practice, and we would not presume to reframe it as one. The point of this article is only that it can be done without harm.

Who benefits, who should be careful, a summary table

Situation	Guidance
Healthy adult, water permitted	Generally fine; eat sensibly when breaking
Diabetes on insulin or sulfonylurea	Doctor first, doses need adjusting
Diabetes on metformin only	Lower risk; still discuss
Pregnancy / breastfeeding	Exemptions exist and are appropriate
Kidney disease, heart failure, diuretics	Doctor first
On BP medication	Rise slowly; watch for dizziness
Elderly and frail	Generally not advised
Waterless fast, summer, high-risk	Avoid
Acute illness, recent surgery	Not advised

What a product can and cannot do here

We manufacture digestive and electrolyte products, and seasonal demand around fasting periods is real.

What is sayable: the recognised role of electrolytes in maintaining normal hydration; traditional use of digestive herbs for comfort; fibre’s role in normal bowel function.

What is not: that any product makes fasting safe, replaces medical advice, enables a diabetic to fast without adjusting medication, or “detoxifies” during a fast. The first three are dangerous and the last is not supported.

And our position for brand owners selling into the vrat season: the useful, honest product here is one that fills the vrat plate’s actual gap, protein and electrolytes, rather than one positioned as making the fast more purifying. The gap is real and nobody is addressing it.

The short version

1. Diabetes on insulin or sulfonylureas, see your doctor before fasting. Doses usually need changing.
2. Medical exemption is legitimate in most traditions, and widely accepted.
3. The vrat diet is often the bigger problem than the fast, sabudana and aloo, deep-fried, with no protein or vegetables.
4. Fix it within the rules: dahi, paneer, nuts, makhana, rajgira, and a sabzi. Roast rather than fry.
5. If water is permitted, drink plenty. Waterless fasting in summer, in a high-risk person, is where emergencies come from.
6. Break it the traditional way, water, fruit, wait, then a normal meal.
7. Hypoglycaemia symptoms mean break the fast now. Every tradition allows it.
8. Checking blood sugar does not break a fast.
9. Taper caffeine beforehand to avoid the headache.

Related: why we do not recommend juice cleanses and what “liver detox” actually means.