The Wellness Edge

Intermittent Fasting vs. Prolonged Fasting

Explore the healing powers of fasting with this comprehensive guide to Intermittent, Prolonged, and Fasting Mimicking Diets.

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Fasting has been practised for centuries for various reasons, including spiritual, cultural, and health purposes.

With the rise of the obesity epidemic and related health issues, fasting has gained popularity as a dietary intervention for weight loss and improved metabolic health.

Different Types of Fasting

Two popular fasting methods are intermittent fasting (IF) and prolonged fasting (PF), also known as extended fasting.

While both methods involve restricting food intake, they differ in duration and frequency. Let’s dive into both types, looking at the scientifically-proven benefits to our wellbeing, as well as one you may not have heard of – the Fasting Mimicking Diet (FMD) developed by Dr. Valter Longo.

Let’s explore the science together.

Intermittent Fasting

Intermittent Fasting involves cycling between periods of eating and fasting, with several variations in the ratio of fasting to feeding. The most common types of IF are the:

  • The 16/8 method: fasting for 16 hours and eating within an 8-hour window
  • The 5:2 method: eating normally for five days and restricting intake to 500-600 calories for two non-consecutive days.
  • Alternate-day fasting: eating normally one day and fast the next
  • The Eat-Stop-Eat method: fasting for 24 hours once or twice a week.

IF has gained popularity because it is relatively easy to follow and flexible. You don’t have to eliminate any specific foods, and it allows you to enjoy social eating occasions, an important aspect of overall wellbeing.

The Benefits

IF has been shown to promote weight loss, improve insulin sensitivity, reduce inflammation, and lower the risk of chronic diseases such as type 2 diabetes, cardiovascular disease, and cancer.

Prolonged Fasting

On the other hand, prolonged fasting involves complete abstinence from food for an extended period, typically 3 to 7 days or longer. PF is more challenging to follow than IF, as it requires a significant amount of willpower, discipline, and preparation.

How Does It Work?

During prolonged fasting, the body shifts from using glucose from food as the primary energy source to using stored fat through a process called ketosis.

The Benefits

PF has been shown to promote autophagy, a natural cellular process that clears out damaged cells and promotes the regeneration of healthy ones, and stem cell activation, which stimulates the growth of new cells and tissues.

Go With Care

While it may seem extreme and risky to not eat for extended periods of time, prolonged fasting can be done safely under professional supervision and with proper preparation and precautions.

This style of fasting is not recommended for certain groups, such as pregnant or breastfeeding women, children, people with certain medical conditions, and those with a history of disordered eating.


Dr. Valter Longo, a leading expert on fasting and ageing, has developed a novel fasting-mimicking diet (FMD) that provides the benefits of prolonged fasting while still allowing for some food intake.

You Can Eat While Fasting?

The FMD is a low-calorie, low-protein, low-carbohydrate, high-fat diet designed to induce a fasting-like state while minimising the risks and discomforts of prolonged water fasting.

The FMD is typically done for 5 consecutive days every 1-6 months, depending on individual needs and goals.

Physical Benefits

The Fasting-Mimicking Diet has been studied extensively in animal and human trials and has been shown to promote many of the same benefits as prolonged fasting, including autophagy, stem cell activation, and reduced inflammation, while also improving metabolic markers such as blood glucose, insulin, and cholesterol levels.

This style of fasting has also been shown to have potential therapeutic benefits for a range of conditions, including cancer, autoimmune diseases, and neurodegenerative diseases.

Mental Wellbeing Benefits

In addition to the physical benefits, the FMD may also have positive effects on mental health. For example, research has shown that prolonged fasting can help to improve mood and reduce symptoms of depression and anxiety. This may be due to the fact that fasting can stimulate the production of brain-derived neurotrophic factor (BDNF), a protein that helps to support the growth and survival of neurons in the brain.

And the winner is…?

While both intermittent fasting and prolonged fasting can provide amazing health benefits, the unique benefits of prolonged fasting, particularly in the context of the the fasting-mimicking diet, make it an important tool to reset body and mind quickly and effectively.

Metaphorically speaking, Intermittent Fasting can be compared to walking up the stairs, while a Fasting Mimicking Diet is like taking the elevator.

Ultimately, everybody is different, so why not experiment with what style of fasting is best for you and your body? Talk with our fasting expert, Ben, about what is right for you.

Interested in using fasting to boost your health?

We’ve been helping people discover the transformative and restorative practice of fasting for over 10 years at Aro Ha Wellness Retreat.

To assist our global community, we offer a seasonal online guided cycle of The Fasting Mimicking Diet.

5-Day Online Fasting Cleanse

The Seasonal Renew is your quarterly ritual of self-care. With our online 5-day fasting-mimicking diet, you’ll receive:

  • a new meal plan made of simple plant-based recipes
  • a shopping list
  • complementary wellness practices such as yoga videos and meditations.
  • Professional guidance during live Zoom calls and ongoing support via the community page.
  • User-friendly platform

This seasonal program is an opportunity to reset body and mind, while staying on track with healthy habits and a positive relationship with food.

Questions about this blog or the Seasonal Renew?

Sending hugs,

The Aro Ha team