By now, the low-carb diet’s refrain is a familiar one:Bread is bad for you. Fat doesn’t matter. Carbs are the real reason you can’t lose weight.The low-carb universe Dr. Atkins brought into being continues to expand. Low-carb diets, from South Beach to the Zone and beyond, are still the go-to method for weight-loss for millions. These diets’ marketing may differ, but they all share two crucial components: the condemnation of “carbs” and...