I'm somewhat of a veteran of various types of fasts, and have a few thoughts:
1) Whenever I do any kind of food a caloric restriction, I assume my body will start doing a lot of "house cleaning" of debris that has built up over time. Some of this debris — such as heavy metals — can be harmful if allowed to float through our circulatory system for too long. So I always take a gentle chelation supplement, with my favorites being charcoal capsules and bentonite clay, to readily adsorb these dangerous metals (and other chemicals).
2) Toxins will be excreted at increased rates during a fast, and the skin is a major detoxification organ. Doing detox baths with things like epsom salts can be very helpful in this regard — besides having the added benefit of adding Magnesium into the body. I also add a teaspoon of sodium thiosulfate to the bath water to remove the chlorine. The relaxing nature of taking these baths is also helpful, as trying to reduce stress as much as possible is always important during fasting.
Sodium Thiosulfate — "May" Help w/ Hearing Loss and/or Tinnitus
I also make a bentonite clay "slurry", and apply a very light layer over most of my skin. You can't really see it after it's applied, and for me it feels good. BTW, it's not unusual to get various kinds of skin eruptions during a fast, such as boils, which is an attempt to eliminate toxins that are not being removed by other detoxification organs, such as the liver. I also like to drink a lemon/apple cider vinegar drink during a fast to support liver function. -- (I'm a big believer in clay therapy of all kinds).
3) I'm not too keen on water only fasts. I think they were likely quite safe and beneficial a 100 years ago, but there is so much contamination built up in our environment, and much of that ends up in our bodies, creating all kinds of havoc that most of modern medicine knows little about. So I prefer to do what I call "modified fasts" of all kinds instead. A favorite of mine is to buy organic carrot juice at Walmart, and add to it some magnesium threonate, and a variety of "juice powders".
These juice powders are a very concentrated nutrition, and have about 20x nutrition more than regular powders. My favorites are wheatgrass juice powder, and beet juice powder. Not only do they provide much needed micronutrients, but they also help considerably in helping eliminate the increased circulating toxins from the body. Besides that, I feel these powders sharpen my brain, and add a lot of resilience to my whole neurological system. Which of course helps me relax and enjoy the fast.
Sometimes I'll notice a "softening" of my tinnitus during a fast. But if not, I always seem to notice a difference in my "perception", making it at least somewhat easier to tolerate. One thing I never do is allow my system to feel overly stressed during one of my modified fasts. I always do them with the intention of feeling better, and enjoying myself more. For me, that's much harder to do one doing a water fast only. I think water fasts may have their place, but it works much better for me to focus on modifed fasts. This is just a partial snapshot of my fasting protocol(s).
One other supplement I like to take while fasting is lipsomal vitamin C, which also aids considerably in toxin removal. I also take it regularly when not fasting.
Best to All...