Intermittent Fasting: What is it, Benefits, How to do it & Side Effects

This article is reviewed by an expert

Intermittent Fasting What is it Benefits How to do it Side Effects 1 5 11zon

What Is Intermittent Fasting?

As the name suggests, intermittent fasting means eating or fasting in specific intervals. It is an eating pattern that alternates between periods of fasting and eating. Rather than focusing on what foods to eat, it emphasizes when to eat them. The most common methods of intermittent fasting involve daily fasting windows, such as the 16/8 method (16 hours of fasting, followed by an 8-hour eating window) or alternate-day fasting, where you eat normally on certain days and restrict calorie intake on others. Intermittent fasting has gained significant popularity in recent years due to its potential health benefits and effectiveness for weight management, but it is also popular with athletes, fitness buffs and anyone interested in a healthy lifestyle because of a variety of potential health benefits.

What Are The Benefits Of Intermittent Fasting?

Some of the proven intermittent fasting benefits include:

  • Weight loss and visceral fat reduction

The use of intermittent fasting for weight loss is what has made the dietary approach so popular and with good reason. By restricting the eating window, intermittent fasting can lead to a calorie deficit, which may promote weight loss. Intermittent fasting can help you lose weight and belly fat, without having to consciously restrict calories by following a strict diet. Some of the weight loss benefits may also be linked to better insulin control, which reduces food cravings. No matter the mechanism of action, the benefit is clear as an analysis of 27 trials showed weight loss in all cases 1.

  • Improved thinking and memory.

Studies have shown that intermittent fasting can even boost cognitive function in older adults who suffer from mild cognitive impairment because of its effects on metabolism and biochemicals 2. Cognitive benefits are not limited to the aged or those with cognitive impairment however, as intermittent fasting is also thought to be protective against the development of neurological disorders.

  • Better heart health

Intermittent fasting is often recommended as a cardioprotective diet because research suggests that it could lower the risk of a variety of heart diseases 3. This benefit is linked to other effects of intermittent fasting such as better weight management, improved blood pressure, better cholesterol levels, reduced oxidative stress, optimization of circadian rhythms and improvements in other heart-related measurements.

  • Increased longevity

Studies suggest that intermittent fasting may extend lifespan by affecting cellular and molecular pathways that influence aging 4. These mechanisms are not yet fully understood, but from what we know Intermittent fasting triggers a metabolic switch that enhances cellular repair processes, such as removing waste material from cells, and increases the body’s resistance to oxidative and metabolic stress.

  • Fight Chronic Diseases 

Intermittent fasting can modulate several factors that are linked to inflammation and oxidative damage, which are involved in many chronic diseases 5. It may help prevent or reverse diabetes, cardiovascular disease, cancers and neurologic disorders by affecting insulin sensitivity, inflammation, cellular stress response and gene expression.

intermittent fasting benefits

How To Do Intermittent Fasting

  1. Choose an intermittent fasting method: There are several approaches to intermittent fasting. To get started you can choose between the 16/8 method (fasting for 16 hours and having an 8-hour eating window) or alternate-day fasting (fasting every other day or restricting calorie intake on fasting days).
  2. Start slow: It can take time for your body to adjust to the new eating pattern. If you’re new to fasting, begin by gradually increasing your fasting window. For example, if you currently have an 8-hour overnight fast, extend it to 10 hours and then gradually progress to your desired fasting duration.
  3. Plan your eating window: For instance, if you choose the 16/8 method, decide on an 8-hour window that works for you, such as 12 pm to 8 pm or 10 am to 6 pm. Adjust the timing based on your schedule and preferences.
  4. Stay hydrated: Drink plenty of water throughout the day, especially during fasting periods. It can help curb hunger and keep you hydrated.

Focus on nutrient-dense meals: During your eating window, prioritize whole, nutrient-dense foods. Include a variety of fruits, vegetables, lean proteins, whole grains and healthy fats in your meals. This will help provide essential nutrients while promoting satiety.

Intermittent Fasting Side Effects

Although generally considered safe, following an intermittent fasting schedule can cause a few side effects and may be ill advised for some people.

  • Initially, you may experience increased hunger and cravings during fasting periods. However, these feelings often subside as your body adjusts to the new eating pattern.
  • Some individuals may experience temporary fatigue or decreased energy levels, particularly during the adaptation phase. 
  • For some people, fasting or eating close to bedtime may interfere with sleep quality. Experiment with different fasting and eating window timings to find what works best for you.
  • If you’re not consuming a well-balanced diet within your eating window, there’s a risk of inadequate intake of essential nutrients. 


Although the benefits of intermittent fasting are undeniable, it is worth noting that intermittent fasting is not suitable for everyone, particularly those with certain medical conditions or individuals with a history of disordered eating. Consulting with a healthcare professional or registered dietitian is recommended before adopting any significant dietary changes.


What is the best time for intermittent fasting?

This will vary for different individuals and should be customized according to what works for you. For example, if you sleep from 10 pm to 6 am (8 hours) a 12 hour fast from 8 pm to 8 am would be ideal.

What is the best duration for fasting?

12 hour fasting periods are regarded as the safest as fasting for longer periods such as over 16 or 18 hours a day is linked to a higher risk of gallstones.

Does sleeping also count as fasting period?

Yes, when intermittent fasting, your sleep duration is also included in the fasting period.

Disclaimer: This article is written from a health and lifestyle perspective. It is for general information and not meant to substitute any medical advice. Please consult your doctor for appropriate medical consultation.



Dr Sunanda Ranade

Sunanda Ranade is Vice-Chairman of the International Academy of Ayurved, Pune, India, and an expert Ayurvedic gynecologist and nutritionist. She has been working in this field for the last 47 years. Dr. Sunanda Ranade holds a Doctorate in Ayurveda. She is also the author of several books on Ayurveda and Yoga, which have been published in Marathi, English, Spanish, and Portuguese.