People are fasting for 72 hours! Is this beneficial, safe? Read to know

This post, which had more than 1.5 million views, left several wondering if this was true and if it is safe to fast for 72 hours. South First spoke to doctors to understand if it is safe and beneficial to fast for 72 long hours.

Also read: Intermittent fasting: Is it good for weight loss or just another fad?

What is 72-hour fasting?

Renowned Neurologist Dr Sudhir Kumar of Apollo Hospital in Hyderabad, who’s also popular on X for answering several queries on diet, exercise and cardio explained to South First what 72-hour fasting is.

“A 72-hour fast, also known as a 3-day fast, is a type of prolonged fasting where an individual does not consume any food or caloric beverages for a continuous period of three days,” he said.

“During this period, he/she typically consumes only non-caloric beverages like water, herbal tea, or black coffee without sugar.”

“The goal of a 72-hour fast is to promote various health benefits, including autophagy (cellular cleaning and repair), fat loss, improved insulin sensitivity, and potential mental clarity,” he said.

Is it beneficial to fast for 72 hours?

Many people in India are interested in intermittent fasting, including the 72-hour fast, primarily for its potential weight loss benefits.

However, the effectiveness of this fasting method depends on several factors. Dr Sudhir Kumar said, many people wonder if extended fasting is safe or beneficial.

“There are two primary benefits to extended fasting. Firstly, it leads to calorie restriction, making it advantageous for individuals dealing with obesity, overweight issues, or diabetes, as it can lead to improvements in their health parameters. Secondly, extended fasting shifts the body from using glucose to fat metabolism, which can help those looking to lose weight,” he said.

However, he said regarding the potential benefits of extended fasting like 72 hours, there is some hope but limited human data.

“Most studies on these benefits have been conducted on animals, showing reduced cancer cell multiplication and increased longevity. However, these effects have not been conclusively proven in humans yet,” Dr Sudhir Kumar explains.

Meanwhile, citing few studies on the benefits of this kind of extended fasting, Shashikant Iyengar, certified metabolic health coach and low-carb practitioner, told South First, “Extended fasting is particularly beneficial, especially for individuals with a higher percentage of body fat. It is also useful in managing certain neurological disorders and some mental illnesses, such as cancers, neurodegenerative disorders, and epilepsy. Additionally, it aids in regaining insulin sensitivity,”

“The benefits of autophagy are observed during extended fasting. Furthermore, the body undergoes a shift towards using fat as its primary fuel source,” he added.

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Is it safe to fast for 72 hours?

Dr Sudhir Kumar explains that it’s important to note that during fasting, staying well-hydrated with water, green tea, black coffee, and lime water is essential to avoid dehydration.

He said the safety of extended fasting largely depends on the individual’s health and proper understanding of what they are doing.

It is generally considered safe for healthy individuals, but those with medical conditions should only attempt it under medical supervision, the doctor added.

Dr Sudhir Kumar elaborated that in terms of specific fasting durations, intermittent fasting, such as the 16:8 or 18:6 method, is commonly practised and has some scientific support for its benefits in conditions like type 2 diabetes, prediabetes, and obesity.

Alternate-day fasting is another approach where one day involves regular eating, while the next day has calorie intake reduced to approximately 28 percent of daily needs.

“Beyond these methods, longer fasting durations like 24, 36, 48, or 72 hours are considered experimental, with limited evidence supporting their safety or benefits. It’s important to approach fasting with caution, stay well-hydrated, and consult a healthcare professional when considering extended fasting,” he said.

How many calories do adults need per day?

According to doctors, on average, an adult needs around 2,300 calories per day to maintain their body weight, considering their physical activity level and Basal Metabolic Rate (BMR).

Therefore, a 72-hour water fast can result in a calorie deficit of approximately 7,000 calories. While this can be effective for weight loss, it can also be risky, explain doctors.

Shashi Iyengar said extended fasting, especially for periods like 72 hours, is a significant physiological challenge.

To ensure a safe and effective fasting experience, it is highly advisable to undertake it under the guidance of a knowledgeable and experienced expert or healthcare professional.

Representational image.

Such experts can provide personalised recommendations, monitor your progress, and address any potential issues that may arise during the fast.

He added that, during an extended fast, the body may experience changes in its electrolyte balance.

To counteract this, electrolyte supplementation is crucial. Electrolytes, including sodium, potassium, and magnesium, play essential roles in various bodily functions, and maintaining their balance is important for overall health.

Proper supplementation helps prevent electrolyte imbalances that can lead to adverse effects such as muscle cramps or fatigue.

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Loss of muscle mass

During extended fasting, it’s important to acknowledge that some loss of muscle mass may occur, said Iyengar.

This happens because the body needs to meet its energy demands, and it may break down muscle tissue for fuel, particularly if glycogen stores are depleted. However, it’s crucial to understand that this loss is typically not severe and can be regained.

Dr Sudhir insisted that maintaining adequate hydration is essential throughout the fasting period. Even though you are abstaining from food, it is essential to drink enough water to prevent dehydration.

“Dehydration can lead to a range of health issues, including dizziness, headaches, and decreased energy levels. Adequate hydration helps sustain bodily functions and ensures that you remain comfortable and safe during the fast,” Sudhir added.

However, he warns that several of them think of running marathons post-fasting, this may not be a good idea, he said.

Also, those with health complications including diabetes, hypertension or any other should always consult their physician before taking up any such fasting, explains Dr Sudhir Kumar.