For me the brain fog lifted after 2-3 months on the diet and continuously improved throughout my treatment. I still have a tiny bit of brain fog after 1 year on the diet.
I recently started to take this supplement called PS-100 (phosphatidylserine) and it boost brain activity. It aids in memory, sleep, and a whole host of other things. It replenishes/heals your inner neuro membrane and has no side effects.
I have used both the integrative thereaputics and pure encapsulations brands. Take 1 capsule before bed.