Upavaasa Yoga, or fasting, is an ancient practice that provides numerous health benefits. It allows the digestive system and other organs to rest and regenerate. Fasting can help treat over 150 diseases by boosting immunity. The document recommends different types of fasting based on age, including water-only fasts, fruit and juice fasts. Regular periodic fasting is suggested to promote longevity and good health. Fasting should be done safely under medical guidance.