Fasting is an ancient practice in the science of Naturopathy, and before beginning a fast, one's individual constitution is taken into account. Since the digestive system is in a resting state during a fast, it is crucial to avoid unduly taxing the body's digestive fire, while keeping the fast. When one fasts, the digestive fire is triggered; in the absence of food, the digestive fire or agni gradually burns away, dissolving any toxins that have lodged deep within the intestinal tract.