I don't know too much about South Beach, but I know that if I had to deprive myself of something (carbs), I would want it more. So, why not try something where you get 2 starches a day? I did LA Weight Loss, but then they went bankrupt.

But, I still use their eating plan, and at my current weight, I get 2 proteins, 2 starches, 2 dairys, 3 fruits, 3 veggies, 2 protein bars (Luna or otherwise), and 1 Fat each day. The serving sizes are predetermined, and you can use receipes as well as regular foods. That has really worked for me.