Therapeutic Fasting – A Scientific Perspective on the Benefits and a Practical Guide
Fasting has been used for centuries as a method for cleansing and restoring the body. Modern science over recent decades has confirmed that periodic abstinence from food brings significant benefits to metabolic and cellular health. When a 24–36 hour fast is performed correctly, mechanisms such as autophagy, ketosis, and increased growth hormone secretion are activated in the body, supporting deep regenerative processes.
Autophagy – Cellular Self-Cleansing
Autophagy is a process of cellular self-cleansing in which damaged proteins and organelles are broken down and recycled. This maintains cellular health and reduces the risk of chronic diseases, including neurodegenerative conditions. Discoveries in this field, for which Yoshinori Ohsumi was awarded the Nobel Prize in 2016, show that autophagy is significantly activated during prolonged calorie restriction, typically after 16–24 hours without food.
Ketosis – An Alternative Fuel for the Body
Another key process is ketosis. When glycogen stores in the liver are depleted, the body begins using fat as its primary energy source. As a result, ketone bodies are formed, which serve as an efficient fuel for the brain and muscles. This state not only promotes fat burning but also improves mental clarity and cognitive function.
Hormonal Changes During Fasting
During fasting, growth hormone levels can increase 2–5 fold, which helps preserve muscle mass and stimulate recovery processes. Increased insulin sensitivity is also observed, reducing the risk of type 2 diabetes and metabolic syndrome.
Preparing for a Fast
To conduct a 36-hour fast starting on August 19, 2025, it is necessary to prepare your body. The day before, it is advisable to eat a low-carbohydrate diet – leafy greens, healthy fats such as avocado and olive oil, fish or eggs. This reduces glycogen stores and helps the body transition more quickly to fat burning. The last meal on the evening of August 18 should be moderate and balanced, for example a salad with olive oil, broccoli, and salmon. Hydration is also important – consume 2–3 liters of water, and you may add a pinch of sea salt to maintain electrolyte balance.
How the Fast Progresses
The fast begins after the last meal on August 18 at 8:00 PM and continues until 8:00 AM on August 20. During this period, you may drink water, unsweetened herbal tea, and black coffee without sugar. If you feel weakness or headache, it is helpful to add a little magnesium or potassium. Light physical activity such as walking or yoga is suitable, while intense workouts are not recommended due to limited glycogen stores.
Hunger symptoms are usually strongest between the 8th and 16th hour of fasting. They can be alleviated with water, tea, or a short period of rest. After 12–16 hours, the body begins to enter ketosis, and after 24–36 hours, autophagy and hormonal changes become more pronounced.
How to Break the Fast
Breaking the fast should be done gradually. It is appropriate to start with bone or vegetable broth, a salad with olive oil, or a small amount of cooked vegetables. Throughout the day, it is good to consume several small meals with moderate amounts of protein, healthy fats, and gradually introduce complex carbohydrates. Heavy, high-carbohydrate meals are best avoided in the first hours after fasting to prevent a sharp insulin response.
How Often Is It Beneficial to Fast?
Repeating a 24–36 hour fast once a month is sufficient to maintain metabolic benefits, while shorter intervals such as the 16:8 regimen can be practiced more often. It is important to note that prolonged fasting is not suitable for people with diabetes, chronic diseases, or for pregnant women without medical supervision.
Conclusion
Accumulated scientific research confirms that fasting is a powerful tool for improving metabolic health, reducing inflammation, and stimulating cellular renewal. With proper planning, it is a safe and effective method for optimizing body functions. Periodic fasting is not just a challenge – it is a way to “restart” your body, improve your metabolism, and feel more energetic. With proper preparation, hydration, and hunger management, you will maximize the benefits of autophagy, ketosis, and growth hormone. Start with confidence, listen to your body, and enjoy the journey to better health!
Sources
Longo, V. D., & Mattson, M. P. (2014). Fasting: Molecular mechanisms and clinical applications. Cell Metabolism, 19(2), 181–192.
Mizushima, N., & Komatsu, M. (2011). Autophagy: Renovation of cells and tissues. Cell, 147(4), 728–741.
Alirezaei, M., et al. (2010). Short-term fasting induces profound neuronal autophagy. Autophagy, 6(6), 702–710.
Newman, J. C., & Verdin, E. (2014). Ketone bodies as signaling metabolites. Trends in Endocrinology & Metabolism, 25(1), 42–52.
Ho, K. Y., et al. (1988). Fasting enhances growth hormone secretion… The Journal of Clinical Investigation, 81(4), 968–975.
Halberg, N., et al. (2005). Effect of intermittent fasting and refeeding on insulin action in healthy men. Journal of Applied Physiology, 99(6), 2128–2136.
