There was an excellent article in the NY Times, a couple of days ago, titled Sweet Potatoes Are Not Just for Thanksgiving Anymore chronicling the growing popularity of sweet potatoes. The basic message is, sweet potatoes are good for you because it is a vegetable that has protein, which is fairly unusual, but it also has complex carbohydrates that don’t spike insulin. Apparently, "sweet potatoes have become the darling of the diabetic and weight-loss set, a lifeline for parents whose children demand fries for nearly every meal and a boon for Southern farmers who are looking to replace tobacco". I must admit, I am very partial to the fries myself. Though, what I cook at home is more healthy since I do not know exactly how to fry them to get that mouth-watering crunchy texture. Sweet potatoes is a common vegetable in India ( I was pleased to find the wikipedia article on that vegetable including its Tamil and Hindi names).
The popular variety of preparation in most parts of India is roasted slow over kitchen coals peeling, cubing and seasoning for a vegetable dish as part of the meal.