Why does anyone bother to read Chocotaco? He's not Primal.
Knifegill's problems digesting starch is clearly an outlier.
To the Original Poster.... Mark has an extremely thin build. His calf muscles are too thin compared to the rest of his body. He probably has more trouble keeping the muscle on than keeping the fat off. Please just look like yourself. But for breaking through a plateau, the fitness forum has a lot of advice.
5'0" female, 43 years old. Started Primal October 31, 2011, at a skinny fat 111.5 lbs. Low weight: 99.5 lb on a fast. Current weight: skinny-fat 106 lbs. Resetting with the 21-day challenge.
MY PRIMAL: I (try to) follow by-the-book primal as advocated by Mark Sisson, except for whey powder and a bit of cream. I aim for 80-90 g carb/day and advocate a two-month strict adjustment for newbies. But everybody is different and other need to tweak Primal to their own needs.