Fasting is the practice of the voluntary cessation of nutrient intake for a set period of time. The Bible has multiple references to fasting, and the medical literature has numerous examples of the benefits of fasting. This book reviews the physical benefits of fasting. The manner in which fasting impacts some organ systems and disease processes are reviewed as well as what happens during the physiological process of fasting.This book also reviews the scriptural references to fasting in both the Old and New Testaments. The biblical indications for fasting are explained.The reader will see how the two overlap. The goal is to promote an understanding of spiritual fasting while also understanding the physiologic mechanisms associated with fasting and how the two possibly relate to each other. Once completed, the reader will have a better understanding of both the physical and spiritual principles of fasting.