Following on from Thomas’ post, I also adopted elements of SCD/GAPS. I am on something of a candida/GAPS hybrid diet. I took Able’s food list, and cut out anything that wasn’t listed as ‘allowed’ on GAPS.
Following advice on this forum, my brain fog disappeared after I finally cut out all grains, and did a cleanse without plant fibre.
Thomas and others gave me a few great tips several months ago, and the brain fog finally left.
So, anything Thomas says, give it a try. It worked for me.
My brain fog is around 80%-90% gone.