While fasting generally involves abstaining from food for a particular period of time, dry fasting involves abstaining from both food and beverages. Proponents claim it can help with weight loss, improve immune function, reduce inflammation, and even delay aging. Importantly, current research does not support these claims. More importantly, the risks are significant.
Without sufficient fluid intake, the body becomes dehydrated, which can lead to symptoms like dizziness, headaches, and fatigue in the short term and urinary tract infections, kidney stones, and lung issues in more severe cases. Long-term dry fasting can potentially contribute to the development of eating disorders like anorexia or binge eating.
For individuals with type 2 diabetes, maintaining adequate hydration and food intake is crucial to managing blood sugar levels. Additionally, dehydration can increase risk for hyperglycemia (high blood sugar) and contriute to a life-threatening condition called diabetic ketoacidosis (DKA) in people with diabetes.
Dry fasting during daylight hours is practiced as part of religious observances like Ramadan, Yom Kippur, and the Bahá’í Fast (what little data there is on the effects of dry fasting comes from looking at these populations). The very young or old, pregnant women, and those who have short term or chronic illnesses are exempted from participating in these obligations. While dry fasting may have deep spiritual or cultural significance in these contexts, it is not recommended outside of a religious context, even for healthy individuals (and certainly not as a weight loss strategy).
Don’t fall for unproven claims. Avoiding both food and beverages for extended periods of time is not a good “diet” choice.