Fasting can be a very controversial topic. I have fasted for 30 days with only water. I did not take any supplements. Over the years, I have success with intermittent and extended fasting. One big challenge with fasting is muscle cramping and muscle fatigue. Reviver Salt Tablets have been my go to choice for the past several months. I have not had any muscle cramping when I use this product along with my fasts. Everyone is different on how their bodies responds and always be careful and listen to your body. Longer fasts should be followed with a trained physician.