I was on for four months. My HDL & Trigs were textbook perfect, but my LDL and Total were very high. I lost close to 40lbs in that time and mentally was sharp, had tons of energy.
I got into my doctor about the numbers and resorted to all the standard keto defenses. I sought out three other physicians, all independent of each other and was tested from scratch. All of them told me to come off the diet, as it was unproven medically.