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Sweet Potatoes Versus Yams: The Difference, Nutritional Information, and a Simple Recipe

Updated on February 27, 2013
A roasted sweet potato. You can tell it's a sweet potato because of the orange interior flesh--1 of 2 types of sweet potatoes sold in US Markets.
A roasted sweet potato. You can tell it's a sweet potato because of the orange interior flesh--1 of 2 types of sweet potatoes sold in US Markets. | Source

Yam or Sweet Potato: What's the Difference?

Although the terms are often used interchangeably in America, they are two different vegetables. Sweet potatoes are a starchy tuber native to the Americas that is distantly related to a potato. Sweet potatoes in the US come in two varieties: one with a creamy, white interior and the other with an orange interior.

Yams, on the other hand, are a tuber native to the tropical regions of Africa and Asia. They generally have darker, bark-like skin on the outside and vary in color on the inside from creamy white to purple. They contain no starch.

Simple, right? So why the confusion?

Going back to Colonial times, African slaves called the sweet potato a yam after the familiar tuber in Africa. This confusion was institutionalized by the USDA who started labeling the darker variety of sweet potato 'yam' to distinguish is from it's paler cousin. Thus, the orange sweet potatoes are often sold as 'yams' but the USDA requires them to also contain "sweet potato" (which is what they really are) in the labeling.

Nutrition Data: Sweet Potato, Yam, and Russet Potato

 
Sweet Potato
Yam
Russet Potato
Calories
90
116
97
Total Fat
0g
0g
0g
Total Omega-3 fatty acids
4.0mg
9.0mg
10.0mg
Total Omega-6 fatty acids
60.0mg
50.0mg
32.0mg
Total Carbohydrates
21g
27g
21g
Dietary Fiber
3g
4g
2g
Sugars
6g
0g
1g
Starch
7g
0g
17.4g
Protein
2g
1g
3g
Inflammation Factor*
+189 (Moderately Anti-inflammatory
-76 (mildly inflammatory)
-59 (mildly inflammatory)
Glycemic Load
9
12
10
Good Source of
Dietary fiber, Vitamin B6, Potassium
Dietary fiber, Vitamin C, Potassium, and Manganese
Vitamin B6, Potassium, and Maganese
Very good source of
Vitamin A, Vitamin C, and Manganese
 
Vitamin C
Serving Amount
100g, baked with skin, no salt
100g, baked with skin, no salt
100g, baked with skin, no salt
Inflammation Factor: The IF (Inflammation Factor) Rating™ estimates the inflammatory or anti-inflammatory potential of foods by calculating the net effect of different nutritional factors, such as fatty acids, antioxidants, and glycemic impact. Sourc

Nutritional Analysis: Sweet Potato or Yams versus Potatoes

As you can see from the nutrition data above, sweet potatoes, yams, and potatoes have a very similar nutritional profile. This is not surprising given that they are all tubers of one kind or another. Where sweet potatoes do have an edge, however, is given the higher amounts of Omega-6 fatty acids and manganese (an essential trace mineral to maintain the integrity of skin and bone), it is moderately anti-inflammatory. This is particular important for people who may be managing chronic illness or high level athletes.

Whether you opt for a sweet potato or a yam, either make a great alternative to potatoes. Because both have more natural (albeit different) flavor than a russet potato, they are less likely to require additives such as butter, sour cream, or excess salt to make them taste good. However, because they usually require a longer cooking time (in excess of an hour), they are not the quickest thing to make for a late evening meal. However, my recipe below makes it a bit more manageable.

A sweet potato before cooking: the interior flesh has been scored in order to expose more of its surface area to heat while roasting.
A sweet potato before cooking: the interior flesh has been scored in order to expose more of its surface area to heat while roasting. | Source

Recipe: Simple Roasted Sweet Potato (or Yam)

This recipe reduces the cooking time by halving the sweet potato or yam and scoring it to expose the interior flesh. Combined with roasting it at a higher temperature, the result is a recipe that takes only 45 minutes rather than the usual 1 1/2 hours.

Cook Time

Prep time: 2 min
Cook time: 45 min
Ready in: 47 min
Yields: Serves 4 people, 1/2 sweet potato or yam ~90g

Ingredients

  • 2 sweet potatoes or yams
  • 1 tbsp olive oil
  • salt and pepper to taste
  • 1/4 tsp nutmeg

Instructions

  1. Preheat the oven to 400 degrees.
  2. Half the yams lengthwise. Cut slits cross-wise into the interior flesh to expose it.
  3. Drizzle the yam with olive oil. Add salt, pepper, and nutmeg.
  4. Roast for 45 minutes or until a fork easily pierces the interior.

Tried This Recipe? Rate it.

3.4 stars from 16 ratings of Roasted Sweet Potatoes

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    • ecogranny profile image

      Kathryn Grace 3 years ago from San Francisco

      Nicely done! Over the years of my cooking life I have read dozens of articles that purport to show one way or another how to tell the difference between sweet potatoes and yams. Several have claimed there is no difference whatsoever.

      In the end, I have to rely on science for the answer, which it appears you have done as well. I thought you might like to know that two horticulturist specialists at the University of North Carolina wrote a short, definitive paper about the difference between the two vegetables, which includes a nice chart delineating the various horticultural factors. All supports your information quite nicely.

      If you would like to link to their page, you can find their article, "What is the Difference Between a Sweet Potato and a Yam?" at http://www.ces.ncsu.edu/hil/hil-23-a.html.

      Thank you for writing this. I have a few recipes that involve yams, er, sweet potatoes. Would you mind if I link to this page, where appropriate, when I discuss their nutritional value and origins?

    • Teresa Coppens profile image

      Teresa Coppens 4 years ago from Ontario, Canada

      You have educated me. I did not know there was a difference between the two. I do know I have been cooking and eating sweet potatoes however. Not only are they great to eat but using the water used to boil sweet potatoes makes fantastic gravy!

    • MickiS profile image
      Author

      MickiS 4 years ago from San Francisco

      Thanks for the comment Claudia. Yams are great, but they are harder to find in the US (the sweet potato is far more common), so I hope you have more luck in Mexico.

    • Claudia Tello profile image

      Claudia Tello 4 years ago from Mexico

      The fact that yams don't have starch makes me want to eat them! I don't know why, but I never pay attention to yams when I am grocery shopping. Next time I will.

      I love roasted sweet potatoes and have never tried them with nutmeg. It sounds nice in my mind so I'll try them with the additional condiment next time.

    • profile image

      tattuwurn 4 years ago

      I love sweet potatoes and yam, respectively called "kamote" and "ube" here in the Philippines. Sweet potatoes can be incorporated into savory dishes to add some thickness and sweetness aside from being made into snacks. Although the sweet potatoes we're used to eating are usually having a white interior.

      Yam is an amazing tuber. Here they are one of the ingredients for cakes, pastries, and ice cream. The "ube halaya" (or ube jam -- or you can call it "yam jam" just for the pun) is also a favorite. And I like its purple color. :)

      I have yet to see the orange-fleshed sweet potato though. :)

      Voted up and interesting, useful, awesome.

    • MickiS profile image
      Author

      MickiS 4 years ago from San Francisco

      Brendl, thanks for the comments.

      They are both vegetables. I'm on your husband's side when it comes to not eating potatoes and sweet potatoes in the same meal! Sweet potatoes are potatoes are cousins, and they are both high in starch.

      Orange versus yellow is not an indicator of yam or sweet potato, by the way.

    • profile image

      Brendi 4 years ago

      I forgot to ask. Are raw sweet potatoes or raw yams toxic? I have considered making coleslaw with raw sweet potatoes(orange flesh). I have heard that there is more carotene in sweet potatoes(orange flesh) than in carrots. Is this true?

    • profile image

      Brendi 4 years ago

      I love baked sweet potatoes including the skins. My husband will not eat a regular potato & a sweet potato in the same meal!!!!! They're both potatoes he says. Poor guy! Mind you he's inclined to be that way anyway. I do not & my hubby doesn't like yams (yellow fleshed) even though the grocery store calls them sweet potatoes. Aren't yams & sweet potatoes classed as a vegetable as compared to a regular white fleshed potato?

    • MickiS profile image
      Author

      MickiS 5 years ago from San Francisco

      Yes, the nutritional data supplied above is for a raw yam, and among the different varieties of yams, this data varies very little.

      Sweet potatoes that are mistakenly labeled yams contain the nutrition data above for sweet potatoes. Like yams, the differences vary little between the varieties.

      The source for the nutritional information above is the United States Department of Agriculture (USDA).

    • profile image

      Valerie 5 years ago

      So, just to be clear, the nutritional information above is for a true yam, not the variety of sweet potato that is referred to as a yam, correct? If so, is the nutritional value for both varieties of sweet potato the same?

    • MickiS profile image
      Author

      MickiS 5 years ago from San Francisco

      Thanks for the comment, ytsenoh. You're very welcome.

    • ytsenoh profile image

      Cathy 5 years ago from Louisiana, Idaho, Kauai, Nebraska, South Dakota, Missouri

      I always thought sweet potatoes and yams were the same thing. I also think that pumpkin pie and sweet potato pie taste very, very similar. I like it all. I do think and agree that sweet potatoes/yams are better for you than white potatoes. Thanks for your hub and recipe.

    • MickiS profile image
      Author

      MickiS 5 years ago from San Francisco

      Thanks. I, too, once thought that. Hence my research that inspired the Hub! LOL.

    • Danette Watt profile image

      Danette Watt 5 years ago from Illinois

      I'm sure I'm not alone when I say that I thought sweet potatoes and yams were the same thing (hence your hub!). Good info, I liked the comparison chart, that was helpful.

    • MickiS profile image
      Author

      MickiS 5 years ago from San Francisco

      KoffeeKlatch Gals, I know! I think I've never really eaten a yam before even though I had been buying a tuber named as such in the store! Thanks for the comment.

    • KoffeeKlatch Gals profile image

      Susan Haze 5 years ago from Sunny Florida

      It's definitely sweet potatoes for me. I don't believe I've even actually eaten a yam.

    • Simone Smith profile image

      Simone Haruko Smith 5 years ago from San Francisco

      How interesting! I had kind of grouped sweet potatoes and yams in my head before reading this Hub. So far as I was concerned, they were all the same thing. I'm not much of a fan since I tend to dislike sweet things, but perhaps it's time I give yams another try. Thanks for the Hub!

    • MickiS profile image
      Author

      MickiS 5 years ago from San Francisco

      As I researching it, rjsadowski, I realized the same thing!

    • rjsadowski profile image

      rjsadowski 5 years ago

      An interesting comparison. From your description, I doubt that I have ever eaten a yam.