Judith,

>1) What exactly does a sweet potato look like?  Is it the purple one on the
>outside, yellowish or orange, cooked? Is this the same as a yam?

True yams grow only in tropical environments and are not sold in American
supermarkets.  What people call red garnet and jewel yams are actually sweet
potatoes.  Some are purple on the outside, some are beige, some are a
peachy-pink color.  Some are magenta inside (red garnets), some are orange
(jewel *yams*), and some are pale gold (jersey sweets or white sweet
potatoes).

Sweet potatoes (listed above) are rich in betacarotene, carbs (30 grams
carbs per 4-oz. sweet potato, a small one at that!).  True yams are not
sweet, not a good source of  betacarotene, and very bland.  Jinenjo mountain
yam is a true yam, sold in Asian supermarkets and eaten in Japan.

Rachel
(who used to teach classes like Sensational Sweet Potatoes)