Benefits of Drinking Water on an Empty Stomach: Boost Your Health from the Start of the Day

World Health Organization – Nutrition and Hydration Guidelines
Mayo Clinic – Water: How Much Should You Drink Every Day?
Centers for Disease Control and Prevention – Get the Facts: Drinking Water and Your Health
National Institutes of Health – Water, Hydration, and Health
NHS – Why Do We Need to Drink Water?
WebMD – The Importance of Hydration