Yams and sweet potatoes are botanically distinct, although the terms are often used interchangeably. Yams have pale flesh and grow in Asia and Africa, while sweet potatoes have bright orange or yellow flesh and grow in tropical regions of the Americas, explains the University of California Cooperative Extension. An 8-ounce serving of yams provides 150 calories compared to 200 calories for sweet potatoes, and both are nutrient-dense foods. However, sweet potatoes hold an edge over yams in certain nutrients.
Carbohydrates and Fiber
Both yams and sweet potatoes offer plentiful carbohydrates--40 grams for yams and 45 grams for sweet potatoes per 8-ounce serving. Fiber is abundant in both vegetables as well, with yams supplying 5 grams and sweet potatoes 7.5 grams. Carbohydrates provide your body with sugars, its preferred fuel source, making both yams and sweet potatoes good sources of energy. Fiber, although not digestible, improves your gastrointestinal health and may help you avoid certain cancers as well as obesity, states the University of Illinois McKinley Health Center.