This is often a controversial subject, but most, including myself, would say that a Water Fast is water only. The reason behind this is that anything else can confuse your body into thinking it will be receiving food. If your body thinks it will be receiving food, it is less likely to start the process of catabolism and cleansing that is what we are looking for in a water fast.

In my earlier days with fasting when I was just experimenting, I tried taking supplements and ended up with a serious stomach ache. Never did it again. Plus taking anything besides water can awaken your hunger or make it so you never get to the point where you no longer feel hungry. This is no fun. I know from experience.

The beauty of Water Fasting is the simplicity: don't have to think about anything else but water.

If you need to take supplements, I would suggest juice fasting instead.

Annata

Supplements are not a good idea during a water fast. Your condition will improve or go away if you fast for a long time.

Post fast diet is very important for any health issue. For Diverticultis you will need to do a Colon Cleanse and eat foods with fiber. Psyllium husk in water every night before bed is also good way to clean your colon.

Take care.

Good wishes.

Archus

your body creates plugs to scour the colon. In order to allow this to happen, you want no food of any kind. Fiber roughly scrapes the colon. all "-itis" diseases are caused by pH imbalance, which leads to your inflammation. Diet change, transitioning to raw food, is your best bet.
Drink distilled water and good luck on your fast.