For the first few days, weeks, or maybe even months, did you happen to feel perfectly fine but notice that your conditioning/athletic performance decreased quite a bit before it started to get better? I did, and now my conditioning is even better than it was before, but for a few weeks there I felt like I could barely keep at it for five minutes.
I'm assuming this has to do with the body getting used to using fat as fuel, recomposing itself and so on. (Very similar to what raw vegans describe, which makes sense considering that's basically only one step removed from this type of eating.) Would be cool to get some anecdotal evidence from others who've done it.