In 2014 my eGFR was 60. My last blood draw, it was 23. I'll get another in September. I started intermittent fasting in 2017. I would eat in an 8 hour window and fast for 16 hours, but I drank a lot of water. 70-90 oz daily. My Neph thought that was ok, as long as I drank that much water. I ate very healthy, no red meat, lots of beans/rice, vegetables, fruits, low salt, etc. My BP always normal, mostly lower than 120/80. But my kidney function continued to deteriorate. My kidney disease is because of 35 years on lithium. I don't the cause of your fluctuations or what your disease is. You mention your immune system. There are a lot of autoimmune diseases that cause kidneys to deteriorate and I think that's where you need to be sure what's going on.

I do not want dialysis. I've made that decision. I would get a kidney transplant, but that's highly unlikely. My goal is to keep my kidney function as stable as I can for as long as I can.