raise your hand if you've ever successfully ran a keto diet...now raise your hand if you've ever felt dumber while on that diet...coincidence? I think not. I've read somewhere that keto diets are notorious for making you feel dumber.
Another cause of feeling dumb while on cycle (for me...maybe not all) is due to increase supplementation of vitamins T, H, and C. I try to eliminate all alcohol from my diet while ON and during recovery. By the way, there is a post on diet discussion board (i think its that board) w/ a recipe for "magic brownies". Me and my buddies tried them out last night...lets just say its a good 5 hours of fun...