I completed 120 hours of fasting. But I used salts recommended by the Snake Diet. My neurologist order tests that measured my inflammation markers Crd and sudrate. Both were significantly improved. In fact, she dismissed me from her care. A short time later, my rheumatologists told me the sarcoidosis was in remission. Yay! I have continued fasting with salts, pickle juice no sugar and/or apple cider vinegar with water.
I haven’t done water only fast. Good luck to you! :)
I’ve been wanting to do the same but I’ve been too nervous to do a fast over 7 days. If I were to do it I’d get a CMP to check liver/kidney function, a lipid panel to check cholesterol and triglycerides, an A1c to see how it affected my blood glucose, and a CRP for inflammation. There are others too that might be interesting but I think these are the main ones.