Yes. No.
Ketosis is the presence of ketones ("short-chain" 2 or 4 carbon fatty acid molecules) in the blood. When serum glucose (blood sugar) is not available, the liver metabolizes fat ("long-chain" > 4 carbon molecules) to produce glycogen and ketone bodies. The glycogen molecules are then further broken down to glucose and water. The ketones are expelled in the urine and respiration.
Poor or good health has nothing to do with it. Just the bodies preference of getting energy from sugar or fat (for Atkins dieters body fat).
The energy from fat does not pass the blood/brain barrier as energy from sugar does.
My mother has a masters in Dietetics. She is terrified of what the Atkins does to the brain, kidneys and liver. My uncle, on the other hand, is an Atkins religious fanatic. But since he has gone on it, he has turned into a moody, fanatical, irritible nut. He scares me now and has blown up with so many irrational accusations against those who love him.
I hope the problem is reversible and he gets back to normal when (I hope) he dumps it. I want my uncle back.