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Multi-Day Fasting and Intermittent Fasting

Updated: Apr 9

Fasting has gained significant attention in recent years for its significant health benefits. Two popular fasting approaches are multi-day fasting and intermittent fasting. While both have their merits, multi-day fasting offers unique advantages that distinguish it from intermittent fasting. In this blog, we will explore the benefits of multi-day fasting and compare them to intermittent fasting. Ideally, practitioners will combine both methods to fully potentiate the profound benefits of a fasting lifestyle.

Multi-Day Fasting: A Brief Overview

Multi-day fasting, also known as extended fasting or prolonged fasting, typically involves abstaining from food for a period of 48 hours or more. During this time, the body undergoes several physiological changes that can yield numerous health benefits.

At Fasting and Thriving Retreats, our team uses an adaptation of the well established Buchinger Method of Fasting, providing participants with daily low calorie juice and broth, rich in essential vitamins and minerals, but calculated to keep you in ketosis during the fast, when combined with the movement and exercise activities provided. This metabolic state of ketosis unlocks a cascade of health-inducing mechanisms in the body that can only be achieved at these high levels through multi-day fasting.

Metabolic Reset and Weight Loss

One of the primary advantages of multi-day fasting is its ability to reset the body's metabolism. Extended periods without food force the body to switch from glucose to fat metabolism, and to remain in that fat burning mode for multiple days. This fat burning process, known as ketosis, promotes weight loss and enhances insulin sensitivity, making it a powerful tool for weight management and diabetes prevention. Multiple sequential days of ketosis unlock powerful healing mechanisms in the body. Additionally, multi-day fasts can be very helpful for participants who desire to change some unhealthy eating habits; i.e. cravings for high sugar foods such as cookies and ice cream that may have become compulsive in nature.

Cellular Autophagy

Multi-day fasting stimulates a powerful surge in the process of autophagy, where cells enhance their efficiency by removing dysfunctional components. Misfolded proteins and damaged DNA are cleaned out, poorly functioning organelles are replaced with new ones, and energy producing mitochondria are renewed. This cellular process, employing a clean-up and recycling crew, helps reduce the risk of life-threatening diseases, including neurodegenerative conditions, cancer, cardiovascular disease, and diabetes. Intermittent fasting, while also promoting autophagy, does not achieve the same depth of renewal as multi-day fasting. To date, multi-day fasting promotes autophagy more universally throughout the body’s many organ systems and at a much higher rate than any other regimen.

Enhanced Hormonal Regulation

Multi-day fasting leads to significant hormonal changes that can benefit overall health. Growth hormone levels rise, promoting tissue repair and muscle preservation. Additionally, fasting triggers the release of brain-derived neurotrophic factor (BDNF), which supports brain health and cognitive function.

Immune System Support

The prestigious New England Journal of Medicine published a review article that concluded "Evidence from decades of animal and human research points to wide-ranging health benefits of intermittent fasting". The article, authored by researchers from the National Institute on Aging, states that intermittent fasting can lead to improvements in conditions like diabetes, cardiovascular disease, cancer, and neurological disorders. Specifically, the review article states that the key mechanism behind the health benefits of intermittent fasting is "metabolic switching", where fasting triggers the body to switch its energy source from glucose to ketones stored in fat. This metabolic shift is said to enhance the body's defenses against stress and initiate repair processes.

Evidence also supports the claims that multi-day fasting can enhance the immune system by promoting the regeneration of immune cells and the production of stem cells. Stem cells find their way to sites of damage in the body that need repair. This may be particularly relevant in situations where the immune system needs a boost, such as during illness or chemotherapy.

Dr. Valtar Longo at UCLA, one of the world’s leading researchers on fasting, recommends a multi-day fast to enhance the immune system. His team found that fasting significantly improved outcomes for patients with cancer undergoing chemotherapy. Older immune cells are retired and new ones are produced. In another study, women with breast cancer, who fasted for even relatively short periods, showed a 64% reduction in the recurrence of their tumors.

Cognitive Function and Mood Regulation

Fasting has demonstrated its capacity to improve cognitive function and provide neuro-protection to the brain and nervous system. In addition to these benefits, multi-day fasting can have a profound impact on mental clarity and focus. Under fasting conditions of controlled calorie restriction, in a process called ketosis, the body uses fat from our stored reserves as its primary fuel. Many individuals report feeling more mentally alert and focused when in ketosis. This heightened mental state can lead to an improved sense of well-being. Research has found that the neurotransmitter GABA is released during fasting, which induces a feeling of calm focus. Additionally, after about 48 hours of fasting, the neurotransmitter dopamine resets, increasing its production and opening up new dopamine receptor sites. Many practitioners have reported that this provides for an enhanced feeling of happiness and a reduction in feelings of anxiety that lasts several weeks beyond the end of the fasting episode.

Longevity and Disease Prevention

Dr. Thomas Seyfried is a renowned professor of biology, genetics, and biochemistry at Boston College. After completing his doctoral studies, he undertook postdoctoral fellowship studies in the Department of Neurology at the Yale University School of Medicine, where he served as an assistant professor in neurology.

Dr. Seyfried's work on fasting, particularly in the context of cancer treatment, revolves around the metabolic theory of cancer. This theory posits that cancer is primarily a metabolic disease rather than a genetic one, with the root cause being damaged mitochondria. Seyfried's research suggests that by altering the body's metabolism through dietary interventions such as fasting, ketogenic diets, and caloric restriction, it's possible to target and manage cancer more effectively. Fasting starves glucose-hungry cancer cells. Additionally, cancer cells cannot use ketones for energy (ketones are our energy source during multi-day fasts). Dr. Seyfried recommends fasting as a primary prevention to cancer, as it has been shown to have a wide range of beneficial effects on cellular protection.

Scientific evidence has established that chronic inflammation is at the root of many health issues, from heart disease to autoimmune disorders. Fasting has been shown to reduce inflammation markers in the body. By reducing inflammation, you can lower your risk of chronic diseases and experience relief from inflammatory conditions. Inflamed cells don’t function efficiently, resulting in symptoms such as brain fog, joint pain, intestinal bloating, fatigue, and others. Chronic inflammation can lead to cancer, stroke, heart disease, and diabetes. Reductions in systemic inflammation from fasting is one of the most health-promoting benefits we can unlock for ourselves.


While intermittent fasting has gained well-deserved popularity for its relative ease of implementation and health benefits, multi-day fasting offers a unique and powerful set of advantages. It activates metabolic reset and surges cellular autophagy to a degree unmatched by other methods. Additionally, it promotes hormonal regulation and immune system support to a greater degree than intermittent fasting. When we incorporate both methods of fasting into our lifestyle, we give ourselves the best of both worlds.

It is important to approach multi-day fasting with caution and consult a healthcare professional, as it may not be suitable for everyone. Ultimately, the choice between multi-day and intermittent fasting should align with individual goals and health considerations, recognizing that each approach has its place in the realm of fasting for health and well-being. However, when both types of fasting are combined in a fasting lifestyle, practitioners harness a powerful strategy to enhance cellular repair, metabolic flexibility, hormonal regulation, cognitive function, and longevity to a degree unattainable by either method alone. Welcome to a lifestyle of happy, healthy fasting!

At Fasting and Thriving Retreats we strive to bring you relevant information regarding a holistic approach to healthy living. A Fasting Lifestyle will help jump start your journey into health.

Take this opportunity to learn more. For an individual, free assessment use the QR Code below and schedule an appointment with one of our experts.

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