Your body will actually go through a couple phases when you begin water fasting. In the first couple days you may notice fluctuations in your energy levels as you body begins to adapt and transition into a state of ketosis. The best part of fasting in my opinion is the autophagy phase, which typically begins between the first and third day of fasting. Autophagy is when the body is able to do a “spring cleaning” of old cells in order to produce new ones, breaking down damaged cells, viruses, and bacteria. During this phase, you may notice clearer skin, a stronger immune system, and less brain fog.