In a nutshell: we're not really sure what carbs are good or bad, but avoid soda and potatoes, and eat more green vegetables. This review of scientific research is a bit confusing and inconclusive, but in its defense that's because the carbs question is pretty complex. A lot of interesting information, but with passages like "Compared with eucaloric glucose ingestion, fructose ingestion favors de novo lipogenesis (24) , which could increase adiposity," it can be slow going, and it probably isn't going to be much help if you just want to find out more about the South Beach Diet. That said, I can't bear to give it too low a rating, because as confusing and contradictory as it might seem, that's science, and I'll take an article, like this one, that basically says "we don't have all the answers" over an article that claims to have the answers but ignores evidence to the contrary.