People who are experienced fasters know how their body and minds react to juice only. The how's whens and why's. Newbie faasters are just learning and the fasting plua the parasite cleansing might be too much for them and they might not finish one or the other. I have a lot of folks who will juice fast or master cleanse while on HUMAWORM and it works out fine HUMAWORM removes parasites and toxins. This strong cleansing of the entire body at the same time can cause die off reactions that can be severe. When die off and detox is severe some folks will require more solid foods to help with the nausea and such. The decision to fast and parasite cleanse is a personal one since each person cleanses differently.