Yams and sweet potatoes are often confused as being the same thing. However, while related, they are actually two different vegetables with distinct differences.
What are yams?
Yams are starchy tubers that originated in Africa and Asia. There are over 200 varieties of yams, but only a handful are commonly consumed as food. The most common yam varieties include:
- Dioscorea alata – purple yam
- Dioscorea polystacha – white yam
- Dioscorea rotundata – white yam
Yams tend to have rough, scaly skin that can be quite difficult to peel. The flesh ranges in color from white to yellow to purple. When cooked, yams have a starchy, potato-like texture and a mildly sweet taste.
What are sweet potatoes?
Sweet potatoes are starchy root vegetables that belong to the morning glory family. They originated in Central and South America. There are many varieties of sweet potatoes, but the most common are:
- Orange-fleshed – have orange flesh and a sweet flavor
- White-fleshed – have white flesh and a mildly sweet flavor
- Jewel – have purple-red skin and orange flesh
Compared to yams, sweet potatoes have smooth, thin skin that’s easily removed. The flesh ranges from white to orange to purple, depending on the variety. When cooked, sweet potatoes have a sweet, almost dessert-like flavor.
Key Differences
While yams and sweet potatoes have some similarities, they have several distinct differences:
| Characteristic | Yams | Sweet Potatoes |
|---|---|---|
| Origin | Africa, Asia | Central and South America |
| Skin Texture | Rough, scaly | Smooth, thin |
| Flesh Color | White, yellow, purple | Orange, white, purple |
| Taste When Cooked | Starchy, potato-like | Sweet, dessert-like |
Some key differences to note:
- Yams have a rough, scaly skin while sweet potatoes have a smooth skin.
- Yams tend to be starchier and drier when cooked.
- Sweet potatoes are sweeter and moister when cooked.
- Yams are native to Africa and Asia. Sweet potatoes come from the Americas.
Can Yams and Sweet Potatoes be Used Interchangeably?
In the United States, yams and sweet potatoes are often used interchangeably in recipes, even though they are different vegetables. However, there are some considerations:
- Yams take longer to cook and have a dryer, starchier texture. So they may not work as well in dishes calling for soft, creamy sweet potatoes.
- The sweeter flavor of orange-fleshed sweet potatoes may overpower a dish if substituted for a white yam.
- The skin of yams is tougher to peel. So leaving the skin on may not work as well.
For best results, use yams and sweet potatoes as called for in recipes based on their unique properties. But in some cases, they can be swapped – just expect slight differences in taste, texture, and cooking time. The amount of sweetness or moisture in a dish may vary depending on the substitution.
Are Yams Healthier Than Sweet Potatoes?
Both yams and sweet potatoes are nutritious vegetables that provide fiber, potassium, vitamin C and other beneficial nutrients. However, there are some subtle nutritional differences.
Yams contain slightly more calories and carbohydrates, while sweet potatoes provide more fiber and vitamin A. Specifically:
- One cup of cooked yams has 160 calories vs. 180 calories in sweet potatoes.
- Yams have 36 grams of carbs including 4 grams of fiber. Sweet potatoes have 41 grams of carbs and 6 grams of fiber.
- Sweet potatoes contain over 400% more vitamin A (over 100% DV) compared to just 2% DV in yams.
So while both are healthy, sweet potatoes do have a nutritional edge – especially when it comes to vitamin A. They contain abundant beta carotene, which converts to vitamin A.
That said, yams and sweet potatoes are comparable in many nutrients. Both can be part of a balanced, nutritious diet when eaten in moderation.
Can You Eat Yams Raw?
Yams contain compounds called oxalate crystals which can irritate the mouth and throat if consumed raw. The fibers are also very tough and difficult to chew. Therefore, it is not recommended to eat raw yams.
Unlike sweet potatoes which are sometimes grated into raw salads, yams should always be cooked first. The cooking process breaks down the indigestible fibers, oxalate crystals and antinutrients, making the yams easier to digest.
Some ways to cook yams include:
- Boiling, steaming or roasting whole yams until soft.
- Peeling and cutting yams into cubes, then frying or roasting.
- Mashing cooked yams into a puree to use in soups.
- Drying cooked yam slices into chips.
Cooking softens the starch and brings out the flavor in yams. The oxalates are reduced to a level that’s harmless to consume.
Can You Eat Yam Skin?
The skin of yams is safe to eat after thorough cooking. However, unlike sweet potato skin, yam skin is very fibrous with an off-putting, rough texture. Most people prefer to peel it before cooking.
If eating the yam skin, the rough surface should be peeled using a vegetable peeler or paring knife. Then the yams can be boiled, roasted or fried with the softer inner skin left intact.
Some benefits of eating yam skin:
- It contains fiber, potassium, vitamin C and other nutrients.
- No nutrients are lost like when peeling the yams first.
- It helps reduce food waste.
However, the unpleasant, chewy texture often deters people from consuming yam skin, even when cooked. It’s really a personal preference.
The Bottom Line
Yams and sweet potatoes have some similarities, but are distinct vegetables:
- Yams have rough, scaly skin and starchy, drier flesh.
- Sweet potatoes have smooth, thinner skin and sweet, moist flesh.
- Yams are native to Africa and Asia. Sweet potatoes come from Central and South America.
- Both are nutritious but sweet potatoes contain more vitamin A.
- Yams should always be cooked first. Sweet potatoes can occasionally be eaten raw.
While you can substitute yams and sweet potatoes in some recipes, the taste, texture and cooking time may differ. For best results, use the vegetable recommended in the recipe. But both can be part of an overall healthy diet in moderation.