Yeah, I too have started intermittent fasting where I don't eat for 16 hours (usually overnight so I get a jump on it and do most of it while sleeping 🙂 ) In the morning I do clear liquids and coffee to keep me going but skip breakfast so my first meal of the day is lunch. I've been doing this twice a week for about 2 months now and it is definitely helping with the brain fog. I can finally read more than one sentence and comprehend what I just read. I can now read about a chapter before my brain taps out and says to take a break so that is progress. Below is a link to an article I read on it.
https://covid19.onedaymd.com/2022/07/autophagy-and-clearing-spike-protein.html