Went through the same thing. It took about 6 months of "peating" to get back to a normal mental state. Id say that caffeine aspirin and B-vit have done the most to get me back to normal. I mentally fell better than I did prior to keto which is probably the lower serotonin. Unfortunately, I don't think my metabolism has fully recovered yet.To get to the nitty-gritty, I went on the ketogenic diet for 3 months and threw a bunch of fasts during that time frame, and at the end of that period I decided to quit because I was experiencing incredibly adverse effects. One of the most immediate ones was my heart pounding outta my damn chest. My hair noticeably thinned everywhere and felt really dry and brittle. My libido took a drastic hit, which was surprising because for as long as I could remember, I suffered from the exact opposite problem. I also became significantly more depressed and subject to low moods. Most disturbing of all was that I felt like a walking zombie who got a lobotomy for a couple months after. My working memory, attentive cognition and verbal memory were all in the damn gutter. I'm a 23 year old male at a healthy weight in case you're wondering.
I took a TSH - T4 panel and the results came out as 3.8 mIE/L TSH and 19 pmol/L FT4 (I took it a few weeks after going off the diet). I haven't taken a T3 test yet but I doubt it's anything out of whack. Am I the only one here who is suffering from the aftermath of a keto diet? I've been off of it for a good five months now and I've been improving somewhat with the help of Peat's dietary suggestions little by little since.