For many of us, the terms sweet potato and yam may be interchangeable. The truth is, generations of Americans have been getting it wrong. Sweet potatoes and yams are not the same. They are two separate foods that aren't even from the same family. We'll tell you when the confusion exactly began, and explain, once and for all, what the difference is between sweet potatoes and yams.
Are Sweet Potatoes Better Than White Potatoes?
Why the Confusion?
If yams and sweet potatoes are different from each other, what caused their names to be used interchangeably? The answer: marketing. In the 1930s, a new sweet potato variety that was larger and sweeter, with soft orange flesh, was cultivated by Julian C. Miller at the Louisiana Sate University Agricultural Center. In order to differentiate it from the sweet potatoes that already existed (smaller, drier and with white or yellowish flesh), sweet potato growers decided to call the new variety a yam—a word that is rooted in the West African words nyam, nyami or enyame, which mean "to eat." Communities of enslaved Africans were the first to refer to the sweet potato as a yam, as it reminded them of the ones they ate in Africa.
Today, USDA regulations require yam labels to be followed by the term "sweet potatoes" when they are technically (and biologically) not yams.
So, What Is a Yam?
A yam is the modified stem or tuber of a tropical vine called Dioscorea batatas. Although they may look similar to sweet potatoes, they are an entirely different species (yams belong to the Dioscoreaceae family and are related to grasses and lilies, and sweet potatoes belong to the morning glory family) and not even remotely related. Yams grow in subtropical and tropical climates like Africa, South America and the Caribbean and are commonly found in cuisines from those areas. There are more than 150 different yam varieties in the world.
Unlike sweet potatoes, most yams are starchy and not very sweet—if anything they taste more like potatoes or yuca (also know as cassava or manioc) than sweet potatoes. They have a more cylindrical shape with rough, scaly skin that's brown and almost tree-bark-like in appearance. Their flesh can range in color from off-white to red or purple, while their flavor is mostly mild and neutral. They are high in carbohydrates with a decent amount of fiber, vitamin C, vitamin B6, potassium and manganese.
Real yams are not widely available in the U.S. They are usually found at grocery stores that specialize in Latin American, Caribbean, Southeast Asian and African products.
What Is a Sweet Potato?
A sweet potato is the storage root of Ipomoea batatas. They grow in warm, temperate climates as well as in tropical regions. They are native to the Americas but grown in many parts of the world. Thousands of different varieties exist today.
Compared to yams, sweet potatoes are shorter. They usually have a bulging middle with ends that taper to a point. In the U.S., sweet potatoes are generally categorized into two types: firm and soft. Firm sweet potatoes usually have generally pale skin and flesh and are drier and less sweet. Soft sweet potatoes are usually darker all around and are moister and sweeter. These orange-fleshed varieties are the ones most commonly mistaken for "yams." Sweet potatoes grown stateside can have thinner skin that ranges in color from yellow to red to purple with flesh that's pale yellow, orange or purple.
Sweet potatoes have a similar nutritional profile to yams, however, they are higher in sugar, vitamin A and beta carotene.
Although peak sweet potato season is in the winter, they can be found year-round at grocery stores in the U.S. Some of the most popular varieties are Hannah (light brown skin and off-white flesh), Jewel (red-brown skin and dark-orange flesh), Garnet (red-purple skin and orange flesh) and Beauregard (dusty-red skin and orange flesh).
Uses for Yams vs. Sweet Potatoes
Yams and sweet potatoes can both be prepared by roasting, steaming, boiling or frying. Substituting real yams in a sweet potato dish would be like using potatoes instead of sweet potatoes in the recipe—it would work, but the end result would taste very different.
We recommend sticking with soft sweet potato varieties for traditional Thanksgiving dishes like Candied Sweet Potatoes and Smashed Spiced Sweet Potatoes, and in dishes where their natural sweetness is key, like these Sweet Potato Waffles. If you're lucky enough to get your hands on some real, fresh yams, try boiling, roasting or frying them.
Bottom Line
A yam is a tuber. A sweet potato is a root. Yams tend to be more cylindrical and have scaly, bark-like skin. Sweet potatoes tend to have a more tapered shape and may be firm or soft with thinner skin. Generally, sweet potatoes taste sweeter than yams. You will more readily encounter sweet potatoes during your regular grocery run, but if you spot a yam, which may be labeled "sweet potato," you'll know the truth.
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FAQs
Yams and sweet potatoes differ in flavor and appearance, and they are not related. Sweet potatoes are in the morning glory family, while yams belong to the lily family. Yams aren't as sweet as sweet potatoes, and they are starchier and drier. Their texture and flavor are more similar to potatoes or yuca.
Which is better, sweet potato or yam? ›
Although both veggies are very close in fiber, protein, vitamin C, and magnesium, sweet potatoes are the healthier option because they are lower in overall calories, lower in carbohydrates, and higher in beta carotene (vitamin A).
Do yams and sweet potatoes taste differently? ›
Sweet potatoes tend to have a more tapered shape and may be firm or soft with thinner skin. Generally, sweet potatoes taste sweeter than yams. You will more readily encounter sweet potatoes during your regular grocery run, but if you spot a yam, which may be labeled "sweet potato," you'll know the truth.
Why are yams not called sweet potatoes? ›
True yams are part of an entirely different genus (Dioscorea; sweet potatoes belong to Ipomoea in the morning glory family) and are more akin to yuca in texture and flavor. Yams are commonly used in Caribbean and West African cooking and can grow as long and thick as an adult arm.
Which is more expensive yams or sweet potatoes? ›
They often look identical, but I've found that "yams" can be as low as 79 cents per pound, while "sweet potatoes" cost $2.49 per pound.
Which yam is the healthiest? ›
Purple yams are rich in antioxidants, including anthocyanins and vitamin C. Antioxidants help protect your cells from damage caused by harmful molecules called free radicals ( 6 ). Free radical damage is linked to many chronic conditions, such as cancer, heart disease, diabetes, and neurodegenerative disorders ( 7 ).
Are canned yams actually sweet potatoes? ›
No, yams and sweet potatoes are not the same. Yams have rough, dark brown skin that is often compared to tree bark, and their flesh is dry and starchy like a regular potato. Sweet potatoes have smooth reddish skin, softer flesh (when cooked), and a sweet flavor.
Can I substitute yams for sweet potatoes? ›
You may not want to substitute true yams in your Candied Yams recipe since their flavor isn't the same as the sweet potatoes in the dish. They can be substituted for sweet potatoes in more savory dishes. Treat them like potatoes to make mashed yams or yam fries.
Can you eat sweet potato skin? ›
You can eat sweet potato skin. It's a good source of fiber, a nutrient that may help lower the risk of heart disease and keep you feeling full for longer periods of time. The next time you make a sweet potato dish, whether it's a roasted side dish or a hearty, cozy casserole, leave the peel on.
Do Americans eat yams or sweet potatoes? ›
' Unless you specifically search for yams, usually found in an international market, you are probably eating sweet potatoes, the Library of Congress states.
Since the “soft” sweet potatoes slightly resembled true yams, they picked up the name and became what you see labeled as “yams” in most U.S. grocery stores.
Are yams ok for diabetics? ›
Its high fibre content contributes to a glycemic index of 54, significantly lower than that of potatoes having a glycemic index of 80. This makes yam better suited for weight watchers, diabetics and those with heart disease as it does not create sharp increase in insulin response.
Are sweet potatoes healthier than yams? ›
Both sweet potatoes and yams are nutritious, albeit completely different vegetables. They are both good to eat as a part of a healthy diet and neither is particularly nutritiously superior to the other. That being said, sweet potatoes contain more vitamin C, vitamin A, fiber, and protein.
What are the three types of yams? ›
The six (6) edible yam species are Dioscorea alata (water yam), Dioscorea rotundata (white guinea yam), Dioscorea esculanta (Chinese or lesser yam), Dioscorea cayenensis (yellow guinea yam), Dioscorea bulbifera (aerial or bulbils yam)and Dioscorea dumetorum (trifoliate or bitter yam) (Purseglove, 1972; Degras L. 1993).
Which cooks faster yams or sweet potatoes? ›
Their tapered tubers have relatively thin, edible skins and sweet flesh that ranges from white to orange and purple. Their tender leaves are a good cooked vegetable, too. Sweet potatoes cook more quickly than yams, are moister, and they taste distinctly sweet.
Is yam or sweet potato good for weight loss? ›
Absolutely. Besides their health benefits, sweet potatoes are a great addition to any weight loss diet. First up, they're very high in fibre — especially soluble fibre. Soluble fibre is excellent because it slows down your digestion and helps you feel full, which can curb the urge to snack between meals.
Which is healthier, purple yam or sweet potato? ›
Sweet potatoes tend to have slightly fewer calories per serving than yams. They also contain a bit more vitamin C and more than triple the amount of beta-carotene, which converts to vitamin A in the body.
What does yam do to the body? ›
Yams are nutrient-dense tuber vegetables that come in many colors. They're a great source of fiber, potassium, manganese, copper, and antioxidants. Yams are linked to various health benefits and may boost brain health, reduce inflammation, and improve blood sugar control.
Are sweet potatoes or yams high in sugar? ›
Despite the name, both sweet potatoes and yams have amounts of sugar that are tolerable for people with diabetes. One cup of sweet potato has 6 grams of sugar, and 1 cup of yams has 0.5 grams of sugar, per the USDA.
