Yes, absolutely. I think this is an important topic that is minimized in the book. I was exhausted...I mean stuck to the couch tired for 2 weeks, and I'm usually the type that is up and about doing something all the time.

My sister-in-law actually passed out on day 4. My office -mate who is 325+ pounds became weak, dizzy, and sweaty and was evaluated in the emergency room.

I'm now a big fan of Atkins but I think adjusting to ketosis can be very difficult for some people. I would be interested to know more about the biochemistry behind it. I would suggest you hang in there, if the symptoms are unbearable up your carbs to 50 or so and gradually decrease them over 1-2 weeks.