Thank you for both your answers, Zonecoach. I know what happened to me wasn't typical, but it was quite serious. I've continued my research, and believe it was due to the more extreme high fat and 20 gram carb Atkins induction I was on. A book called Life without Bread, which recommends around 75 grams carb, talks about the dangers of extreme lo carbing too quickly for some people -- it can stimulate autoimmune problems among other things, which is what I think happened with me. I'm concerned that people are only looking at cardiovascular dangers, HDL level,s etc. and not addressing some other possible dangers of Atkins for some of us. I've been off it and doing Schwarzbein's 75 carbs/day for a week, and I started feeling better yesterday. I think I'm okay for now - through the crisis.

Anyhow, I consider the Zone to be more "balanced" rather than "low". That's probably why people don't have that hard transition. Something sounds right about that to me, but I don't want to make any more changes for my poor body for a while. I will consider switching to the zone in the near future.