Paleo or Mediterranean, makes the most sense in terms of optimal health. I would do a modified Paleo, with good quality dairy and some rice or quinoa. Healthy animal fats and protein are, for me, essential to proper brain function. Your brain is made up of mostly cholesterol. I know when I begin my day with a nice cup of coffee with grass fed butter I feel clear-minded and ready for the day ahead. Add a few eggs and I'm totally ready to start the day. 

I've never reached ketosis, but I need to try it in the future. When I did Paleo for 30 days, I felt incredible. It was also very difficult to follow for a long period of time. I've made the decision to dramatically reduce gluten for the time being, though I know certain gluten replacements are really not that good either.