Fisch, I'm a newly minted zero carber going on two months, and on a typical day I get anywhere from 60 to 80 percent of my calories from (saturated animal) fat. Everyone who says I should be eating fiber apparently worries about what's happening to my insides, but I've had no gastrointestinal problems to speak of. Regarding exercise and weight/fat loss, I still have a bit of stubborn spare tire, but I can see the most obvious changes "in between" intense workouts, during the days I'm recovering. My sessions are no more than 20 minutes in duration and no more often than twice a week, consisting of bodyweight exercises (gymnastic conditioning moves, ow!), heavy weight lifting (low reps), and once a week brief sprints (barefoot, toe-heel). On the days I don't work out, I alternate between walking, gardening, and resting if I feel overly sore.
I can't speak for anyone else, but I see a lot of folks on Charles Washington's Zeroing In On Health site who have trouble losing weight until they decrease or sometimes even TEMPORARILY eliminate exercise, until they reach their desired weight. Taubes pretty thoroughly debunked the notion that exercise helps with weight loss, but that doesn't mean there aren't many other good reasons to do it. The point should be to do it smarter, in a way that promotes optimal health and body composition. Low carbers and primal leaning folks should already be at least somewhat accustomed to going "against the grain" of conventional wisdom. But really, even though it's only a study size of one, in the end the best test is to experiment on yourself. No matter what anyone else says you should and shouldn't eat, only you can judge how it makes you feel when you eat it...
Give me a friendly Christian any day over an asshole atheist.