Nothing completes a barbecue or picnic like a classic potato salad. The following Summertime Sweet Potato Salad from the Taste of Summer Cookbook is a delicious South Beach Diet-approved spin on an old favorite. Yogurt and red wine vinegar make a smooth and tasty dressing for this easy picnic dish. Tarragon can be added or used as a substitute for basil. Since sweet potatoes are available year-round, try serving this dish warm in cooler months; simply drain the potatoes and don't rinse them before adding the dressing.