If you're looking for a food that's almost as old as time, look no further than the sweet potato. Peruvians were known to eat them as far back as 750 B.C., and when Columbus arrived to the New World, Native Americans were already chowing down on them. The orange color and sweet taste are hallmarks of this member of the Morning Glory family, and it's nutritious to boot. Aside from being fat free, they're high in fiber, vitamins A, B6 and C, and they're low in sodium and cholesterol. This makes sweet potatoes a good substitute for their white potato cousins. Here are five tips to make your sweet potatoes sing on your plate.