Fasting as seasons change: what's risky, and why detox is a myth

Very soon, it will be the time of year when we fold away the summer clothes and bring out the light jackets. Mornings turn cooler, afternoons can still feel like summer, and half the office is sniffling. Into this weather comes Sharad Navratri. For many, that means nine days of fasting.Is that a problem? The honest answer is "it depends on you." Fasting isn't automatically harmful, and the season change doesn't turn it into a health hazard overnight. But the timing does matter, and so does the way most of us fast. Here's what the doctors and the research say.THE SEASON IS NOT ON YOUR SIDEDoctors in Delhi-NCR have reported a rise in H1N1 and flu-like illness in the post-rain weeks. AIIMS Delhi's Dr Sanjeev Sinha linked it to the temperature drop that comes with the monsoon. Another analysis estimates that 30-40 per cent of outpatient visits in India during monsoon and winter are due to seasonal infections such as flu, viral fever, diarrhoea and chest infections.The post-monsoon period in India brings influenza and other respiratory infections, while dengue and malaria remain important seasonal concerns," says Dr Rajiv Kovil, Diabetologist and Obesity Expert and Director of Zandra Healthcare. So your body is already working harder than usual. Now let's look at what happens when you add a fast.WHAT HAPPENS INSIDE YOUR BODY WHEN YOU DON'T EATDr Kovil explains it simply. When we eat three meals a day, glucose from food is our immediate fuel. When we fast, "insulin falls and glucagon rises." The liver first breaks down stored sugar. He says liver glycogen is "substantially depleted within about 24 hours," after which the liver manufactures glucose from other sources and the body burns more fat, producing ketones as an alternative fuel for the brain. In a healthy person, he says, this is "usually a controlled physiological adaptation." In diabetes it can be very different."If there is significant insulin deficiency, particularly in type 1 diabetes, fasting combined with very low carbohydrate intake can accelerate fat breakdown and ketone production," Dr Kovil explains. This can lead to diabetic ketoacidosis, which he calls a medical emergency. He adds that people on SGLT2 inhibitors can occasionally develop it even without very high glucose. His verdict: "This is why prolonged fasting in diabetes should never be undertaken casually."For people with diabetes, the biggest day-to-day danger is a sugar crash. A US diabetes expert writing for the National Institute of Diabetes and Digestive and Kidney Diseases calls low blood sugar the number one risk of fasting.DOES FASTING WEAKEN YOUR IMMUNITY IN FLU SEASON?There is no study of Navratri fasting and flu, so nobody can say it definitively does. But the clues point in one direction.An older Michigan State University study found that mice on restricted calories were less prepared to fight off the flu virus. The researcher said a calorie-restricted body is less ready to control early infection. That was an animal study, so treat it as a warning, not proof.On the other hand, research on Ramadan fasting suggests healthy people can get through the month without a higher risk of infection, while people with other health conditions or weak immunity are a different story.Dr Kovil draws the line clearly: "A short, well-planned fast in a healthy person is very different from prolonged fasting accompanied by inadequate calories, protein and micronutrients." His reasoning is that immune cells need energy, amino acids and micronutrients to make antibodies and multiply.His fix is not a miracle food, "There is no single 'immunity booster' food or supplement. The answer is adequate nutrition," meaning milk, curd, paneer, nuts and seeds, permitted vegetables and fruit, enough fluids and enough sleep.If you get a fever mid-fast, don't tough it out. Dr Kovil says: "If fever or significant illness develops, hydration, nutrition, glucose monitoring and recovery should take priority over completing the fast."Another caution comes from the diabetes literature. Dr Martin Grajower, an endocrinologist, says anyone who has had a fever in the past week or so should not fast, because sweating can leave them dehydrated.DOES FASTING DETOX YOU?No. Dr Kovil is blunt about it: "The human body is not a car that needs to be sent for a periodic wash, servicing and 'detox'!"He says we already have a 24-hour cleaning system: "the liver metabolises potentially harmful substances, the kidneys filter and excrete waste, while the lungs and gastrointestinal system continuously eliminate metabolic by-products." And: "There is no convincing scientific evidence that fasting somehow 'flushes toxins' from the body."Outside experts say the same. Columbia University's health service says there is no evidence that fasting is effective for detoxing. The US National Center for Complementary and Integrative Health notes that weight loss on detox diets may simply be because they are very low in calories. A doctor at MD Anderson Cancer Center puts it plainly: "We don't need more help through fad diets."So why do you feel lighter and "cleaner"? Dr Kovil says the feeling is real, but the cause is physiology, not purification. Used-up glycogen releases water, the gut empties, salt and calorie intake fall, bloating can improve, and the body shifts towards burning fat. "These are genuine metabolic adaptations," he says. "Calling all of this 'detoxification' makes good social-media language, but not particularly good metabolic science."To be fair, some researchers study whether fasting triggers cell-repair processes such as autophagy. That is interesting science, but it is not the same as "flushing toxins," and the evidence doesn't come from Navratri-style fasting.YOUR STOMACH DOESN'T KNOW IT'S A FESTIVALDr Vishal Khurana, Principal Director and HOD, Gastroenterology and Hepatobiliary Sciences, Metro Hospital, Faridabad, begins with a surprising fact: "Honestly, your stomach has no idea you're fasting. It runs on its own schedule, constantly producing acid and digestive juices based on your nerves and hormones, not whether there's actually food in there to digest."So after a few hours you might feel burning, nausea or hunger pangs. But Dr Khurana says the bigger problem shows up at the end of the day: "Staying hungry all day and then suddenly dropping a massive, oily, or spicy meal into an empty stomach is a perfect recipe for sudden bloating, reflux, and severe acidity."His line sums it up: "A lot of the time, the fast isn't what makes people sick, it's the feast that follows."He calls it "fasting and feasting." The usual suspects are deep-fried kuttu pakoras, sabudana vada and potato chips, which he calls "incredibly heavy" for an empty, sensitive stomach. Tea and coffee on an empty stomach can also cause "serious burning."Dr Kovil makes the same point from the metabolic side: "The irony is that a Navratri 'fast' can sometimes become a high-carbohydrate, high-calorie diet." He warns that sabudana, potatoes, sweets and sweetened drinks can produce big sugar spikes. "The objective of fasting should be discipline, not metabolic punishment followed by metabolic celebration."A quick myth-bust: "Fasting causes stomach ulcers" is false, says Dr Khurana. "Ulcers are usually caused by an H. pylori infection or relying too heavily on NSAID painkillers." And a burning sensation doesn't always mean "too much acid." It can be a sensitive gut or reflux.Acidity, reflux and GERD are not the same thing. Dr Khurana explains that reflux is when stomach contents splash back into the food pipe. When it happens "all the time and starts disrupting your life," that's GERD. An occasional bout of heartburn doesn't mean you have it.WHEN TO STOP THE FASTNeither doctor wants you to treat warning signs as a test of willpower.Dr Kovil says, "Cold sweats, trembling, palpitations, dizziness, blurred vision, brain fog, unusual irritability, severe weakness, confusion or fainting can indicate hypoglycaemia, dehydration or falling blood pressure." For someone with diabetes, a reading below 70 mg/dL is hypoglycaemia and "must be treated, the fast should be broken."Dr Khurana adds a list of his own: stop if there is repeated vomiting, severe stomach pain, dizziness, fainting or extreme weakness. "Pushing through it isn't doing you any favors."Some symptoms should never be dismissed as "just acidity." Dr Khurana says to see a doctor immediately for "trouble swallowing, black stools, vomiting (especially with blood), sudden weight loss, or severe chest pain."WHO SHOULD CHECK WITH A DOCTORDr Kovil says pregnant or breastfeeding women, people with chronic kidney disease or significant liver disease, frail older adults, those with recurrent low blood sugar or significant low blood pressure, and those recovering from serious illness "should seek medical advice before fasting."Dr Khurana adds anyone with an active ulcer, severe GERD or repeated gastritis.If you have diabetes, the most important advice is this. Dr Kovil says, "Never independently stop, halve or shift diabetes medicines simply because Navratri has started." People on insulin or sulfonylureas can go dangerously low when meals are skipped, while stopping medication outright can cause severe highs. Dr Grajower also discourages fasting for people with an A1C of 9 or above. Tell your doctor how long you plan to fast, and when you plan to eat, before you begin.IF YOU ARE GOING TO FAST, DO IT SMARTLYDr Kovil's Navratri formula is vegetables first, later add protein and healthy fats, move to carbohydrate last, important to eat slowly and eat earlier, also walk afterwards.In practice, start with permitted vegetables, then curd, paneer, milk, nuts or seeds. Make sabudana, potato, kuttu or rajgira the smaller portion, eaten at the end. A 10-15 minute walk after the meal helps reduce the sugar spike.Drink real water. Dr Kovil says most adults can aim for roughly 2-3 litres over the day, adjusted for body size, heat, activity and medical conditions. Tea and coffee should not replace water. Dr Khurana suggests sipping steadily instead of chugging."Protein should not disappear because it is Navratri," says Dr Kovil, who puts the need for healthy adults at around 0.8 g per kg of body weight a day.Dr Khurana suggests a small, simple home-cooked meal with fruit, a few nuts or some curd. Dr Kovil recommends water first, then a light semi-solid meal, then a normal balanced one.Don't lie down right after a heavy meal. Dr Khurana says this is the one rule people always forget. Skip the "detox" mindset.Dr Khurana says that if you're otherwise healthy, "you can absolutely fast safely." But if every fast ends in vomiting, clutching your stomach or living on antacids, "don't just power through it. Figure out what's actually causing the problem."The season has changed, and fasting doesn't have to be an endurance test. Plan it, keep your protein and water up, and go easy at the end of the day.- Ends