Keep digging, you'll find better info on Ketogenic diets than a CW piece in an online Women's Health website. Ketoacidosis is rare, and simply does not occur in non-diabetics, active or not. Look into Dr Seyfried's work, just for starters: http://www.bc.edu/schools/cas/biolog.../seyfried.html
and listen to his interview with Jimmy Moore at Livin la Vida Low Carb. You can get more info on Ketogenic diets at Dr Eades' Protein Power blog among other critically science based blogs and websites.
It is likely our ancestors a mere 300-350 generations ago were in ketosis the majority of their lives.