The 36-hour fasting craze is dividing the health world — miracle or mistake? While many fitness enthusiasts swear by long fasts for rapid transformation, doctors are urging caution before anyone jumps on the trend. And this is where things get controversial…
A growing number of wellness influencers are promoting the idea that skipping food for a full day and a half can reset the body, sharpen focus, and accelerate fat loss. But Dr. Sudhir Kumar, a senior neurologist from Apollo Hospitals in Hyderabad, warns that such extended fasting should not be seen as a universal solution. In a detailed post on social media, he explained that while some healthy adults may handle it without major issues, it’s certainly not risk-free for everyone.
What actually happens during a 36-hour fast
During this long fasting window, people usually stick to only water, plain tea, or unsweetened black coffee. Dr. Kumar calls it a prolonged version of intermittent fasting — essentially, pushing the no-food period far beyond the common 16 or 18 hours. Some participants claim they feel more alert and mentally clear, but others struggle, depending on their daily activity, sleeping patterns, and health conditions.
Possible benefits for some adults
Dr. Kumar acknowledged that limited evidence suggests certain benefits may emerge in otherwise healthy adults. Longer fasts might help improve insulin sensitivity — meaning the body uses insulin more efficiently — and could support calorie control. There’s also a fascinating process called autophagy, where cells naturally clean out damaged components. Extended fasting might help trigger this mechanism, though research in humans remains far from conclusive.
Interestingly, some people report laser-sharp concentration during fasting. Dr. Kumar explained this is likely because the body starts producing ketones, an alternative energy source created when it burns fat for fuel. Longer fasts can also help people observe their genuine hunger cues, ultimately reducing boredom eating or habitual snacking.
The overlooked dangers
And here’s the part most people ignore — the risks. Despite its popularity, water-only fasting isn’t harmless. Dr. Kumar cautioned that going without food for 36 hours may lead to dehydration and electrolyte imbalances, as essential minerals like sodium and potassium aren’t replenished. Some people may experience dizziness, mood swings, or headaches — especially if they attempt strenuous workouts while fasting. Sleep quality can also decline due to rising cortisol, the body’s stress hormone.
He further warned that doing such fasts repeatedly without proper nutrition may lead to muscle loss over time. Another often-missed issue is acidity or gastritis, which can worsen if tea or coffee is consumed on an empty stomach — a habit many fasters don’t realize can backfire.
Who should avoid it completely
Dr. Kumar didn’t mince words: extended fasting isn’t for everyone. He strongly advises against it for people with diabetes, those managing hypertension with diuretics, individuals with low BMI, or anyone dealing with eating disorders or anxiety around food. Pregnant and breastfeeding women should avoid this fasting method entirely.
He also dismantled a popular myth — that fasting ‘detoxifies’ the body. In reality, our liver and kidneys are constantly filtering out toxins naturally. No amount of fasting can magically multiply their effectiveness.
Safe fasting guidelines
For those still determined to try the 36-hour fast, Dr. Kumar outlined four key precautions:
- Drink electrolyte-rich water, not plain water, to maintain mineral levels.
- Avoid intense physical workouts during the fasting period.
- Break your fast gradually with gentle, protein-based meals.
- Limit such prolonged fasts to once a month at most if you’re in good health.
The bottom line
In Dr. Kumar’s words, an occasional 36-hour liquid fast may be tolerable for some healthy middle-aged adults, but it’s certainly not required for fitness or detox goals. He advised stopping immediately if anyone experiences palpitations, dizziness, fatigue, or sleep issues.
So, here’s the question worth asking: Is the promise of sharper focus and faster fat burning truly worth the risks to your body’s balance? Or is the 36-hour fast another case of a wellness trend stretching science too far? What do you think — fad or functional health tool?