All life forms on our planet under the strong influence of a daily light/dark cycle (24-hour rhythms). The basis of this circadian rhythm is the ability to acquire food when is available and store a part of these resources for use during the rest of the day (i.e., the fasting period) as a time for standby and repair and based on ”fasting physiology” (biochemical processes associated with fasting) theory to harvest energy when food becomes available. Disruption of activity-rest cycle due to excessive activity in the 24 hr, indirectly disrupts the natural daily cycle of feeding and fasting, and excessive caloric intake that chronically can be contributes to metabolic diseases and may also accelerate the aging process. Among alternative interventions for the prevention and treatment of chronic metabolic diseases, different forms of fasting (daily, alternate daily, or periodic fasting) have the greatest potential of being integrated into the standard medical care and can promote healthy lifespan by exerting pleiotropic effects, restoring a fasting period or switching to a diet that mimics fasting may be an effective treatment strategy for several chronic diseases.(1)
Because fasting has been ordered in different religions and cultures, many scientists have been looking for scientific reasons of fasting for years, and so far they have achieved substantial results, all of which favor the benefit of fasting. Fasting is defined as a partial or total abstention from all foods, or a select abstention from prohibited foods. Several forms of fasting are proposed. In the present review, we will highlight the most common published protocols in the literature: caloric restriction (CR), intermittent fasting (IF), Ramadan intermittent fasting (RIF), dietary restriction (DR), Christians and Judaism fasts. (2)
Recent studies conducted on these different forms of fasting, showed beneficial effects on animal and human health (3-6). They appear to delay the onset of the diseases such as autoimmune diseases, atherosclerosis, cardiomyopathies, cancer, diabetes, renal diseases, neurodegenerative diseases, and respiratory diseases (7, 8). The present review article will elucidate the fascinating and potent effects of IF on the human health and prevention of disease. In this study, we will describe the various mechanisms involved in fasting. One of the mechanisms that activates in the cytoplasm of all cells during fasting is the autophagy mechanism. The autophagy mechanism with the degradation of aggregated proteins and fat droplets, as well as damaged organelles, toxins and intracellular microorganisms, and waste compounds of the cells, provides the essential nutrients and energy for the survival of the cells. Therefore, in this study, we will characterized the mechanism of autophagy, how to regulate this system during fasting as well as the role of fasting and autophagy in preventing and treating many diseases and cancers.