If you are dealing with brain fog you have to check out this site: www.selfhacked.com
This is NOT my site. This is the best info. on the subject in my opinion and it is free. This is the absolute most comprehensive information I've found on the subject of brain fog and I've been dealing with this for 5 years.
Even if you don't agree with the recommendations, or don't believe that the causes pertain to you, the recommendations are sound and are generally good advice no matter what.
I hope this helps some of you. I have known about this site for a little while and have experienced some benefits in my brain fog from his recommendations, but I haven't applied everything he recommends 100%, so now I am going to put a 100% effort in to beating brain fog.
Going to post this in the AF forum too because many may get some relief from these recommendations.