Pickle, good question!
I'm not entirely sure of the reason behind the extra promotion of brown rice unless it happens to have more nutrients than converted. The GFGCG
says that brown, wild, and converted rice are all good choices. Feel free to eat any from that list as often as your body can handle in Phase 2.
Unlike low carb diets, SBD does stress eating whole foods for health. I figure that converted might have less nutrients than brown or wild, which may be why it isn't promoted as much. I know that Barb uses converted often and enjoys it. I've never tried it. What makes it 'converted'?
Pickle, on another front, you might consider changing your name to something more positive. I'm sure that there are many wonderful aspects of you whether your body may be 'chunky' or not. And when your body is skinny, you'll want a name that reflects that. What about "Pickle Chick"? If you decide to change your name, just send a PM to RuthXXX...she can make the change for you.