Daijiworld Media Network – New Delhi

New Delhi, Aug 25: A 25-year-old woman who adopted a 36-hour intermittent fasting routine to lose weight shed 5 kg in a month, but at the cost of extreme fatigue, lack of concentration, bloating, acidity and sleep disturbances. Doctors warn that while this fasting trend is gaining popularity — with even Bollywood celebrities like Akshay Kumar endorsing it — it could be a double-edged sword.

Explaining the process, experts say a 36-hour fast is an “extended fast,” where one stops eating after dinner on Sunday and resumes only at breakfast on Tuesday. During this period, only water, tea, or calorie-free drinks are permitted. The body switches from glucose to stored fat for energy, a process known as ketosis, followed by autophagy — where damaged cells are recycled.

“After about 12 hours, insulin levels drop, allowing fat to be burned. By 18–24 hours, glycogen is depleted, and the body starts producing ketones, which fuel both brain and body,” says Dr Sudeep Khanna, gastroenterologist. Autophagy, he adds, may offer protection against diseases like cancer and Alzheimer’s, though more human studies are required.

While some fasters report improved focus, many experience tiredness, hunger, irritability and headaches. Dr Khanna notes that this approach may be safe for healthy adults if done with hydration and rest, but not for diabetics, pregnant women, those with eating disorders or people on certain medications.

Endocrinologist Dr Richa Chaturvedi of Indraprastha Apollo Hospital, however, sees more risks than benefits. “Excess fasting produces ketone bodies that can make the blood acidic. Without proper hydration, electrolyte imbalances occur. Dizziness, headaches, fatigue, insomnia, and lethargy are common. Muscle loss, digestive issues, mood disturbances and inflammation are more worrying long-term effects,” she warns.

Doctors also caution against binge-eating after fasting. “Extended fasting can even trigger the body to store more fat as a starvation response,” Dr Khanna points out, suggesting that other fasting formats with shorter gaps may be safer and more sustainable.