Rick, your question reminded me of the low or no-carb diet my first wife and I tried back a long time ago (80's, I think). I don't know if we were doing it wrong or what, but after a week or so, we began to lose our train of thought right in the middle of a sentence. It was very disconcerting. Plus, we began crave carbs so much, it was commonly difficult to sleep.
But then I searched "keto diet" and got this:
Ketogenic diet - Wikipedia, the free encyclopedia
This article is about a dietary medical therapy. For information on ketogenic low-carbohydrate diets as a lifestyle choice or for weight loss, see Low-carbohydrate diet.
A test strip is compared with a colour chart that indicates the degree of ketonuria.
Testing for ketone bodies in urine
The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used primarily to treat difficult-to-control (refractory) epilepsy in children.
So is your reason for doing it for weight loss or to control epileptic seizures? Wait... you're not a child. At any rate, I would think if it's to control seizures, if you are under a doctor's care and supervision, it wouldn't be anything like my experience.