So, my doctor told me to move to a ketogenic diet in the interest of more brain clarity and less brain fog. He goes off to conferences and likely heard about your study above.
I was already on a grain and sugar free Paleo diet, and knew a fair amount about ketogenic diets, so it seemed worth a try.
He suggested cutting back on starchy vegetables and fruit, and adding C8 oil (caprylic acid oil) to my coffee, and beta hydroxybutyrate as you mentioned above and limit food to a 12 hour period of the day.
There's a limit to the health interventions I can manage, but I decided if I could do "casual keto" with those simple changes, it would be worth experimenting.
Armed with ketosis strips from WalMart, I found myself in ketosis by day 2 and my brain fog has been markedly better ever since. I put the BHB with creatine, d-ribose, and some branched chain amino acids in a water bottle I drank at the gym and found my exercise went better than it had in months (I.e. no naps, downtime two!) and I felt better afterwards.
Peter Attia, on the Eating Academy website, has interesting things to say about ketosis. He's a little obsessed and has different health goals than we do, but he did some interesting self experiments, which is how I learned about increased exercise performance.
Now, have to see if the changes stick, it if I adapt and regress... or maybe I'm growing new brain cells, which would be very nice indeed....