Vesipaasto

Vesipaasto, or water fasting, is a fasting practice in which the participant consumes only water for a defined period. The aim is typically to reduce caloric intake and trigger metabolic changes, and it is used both in religious paasto traditions and in contemporary wellness or experimental contexts. Typical durations range from 24 to 72 hours, but some people undertake longer fasts lasting several days or more under medical supervision.

During a vesipaasto the body gradually shifts from glucose metabolism to fat-derived ketones as glycogen stores are depleted. Proponents cite potential benefits such as weight loss, improved insulin sensitivity, metabolic flexibility, and cellular repair processes. However, robust evidence in humans is limited, and benefits are not guaranteed. Potential risks include dehydration, electrolyte imbalances (especially sodium and potassium), dizziness, low blood pressure, and fainting. Vesipaasto is not suitable for everyone, including pregnant or breastfeeding individuals, people with certain chronic diseases (notably diabetes requiring insulin or kidney disease), those with a history of eating disorders, and individuals on medications that require food intake. Medical supervision is advised for extended fasts.

Before beginning, individuals should ensure adequate hydration, plan for gradual refeeding to prevent refeeding syndrome, and monitor symptoms. Reintroduction of foods should begin with easily digestible items such as fluids, broths, and light foods, gradually increasing caloric intake. Vesipaasto is one option among fasting approaches, but it should be approached with caution and personalized medical advice.