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

A roasted sweet potato. You can tell its a sweet potato because of the orange interior flesh--1 of 2 types of sweet potatoes sold in US Markets. Source: Micki Seibel, March 2012

A roasted sweet potato. You can tell its a sweet potato because of the orange interior flesh–1 of 2 types of sweet potatoes sold in US Markets. Source: Micki Seibel, March 2012

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. Source: http://nutritiondata.self.com/

Nutritional Analysis

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.

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

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Yields: Serves 4 people, 1/2 sweet potato or yam ~90g

Ingredients

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: Micki Seibel, March 2012

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: Micki Seibel, March 2012

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

Directions

  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.

How Not To Screw It Up

  1. It’s important to cut the yams in half and expose the interior flesh with the cross-sectional cuts. This is the key to the shorter cooking time.
  2. I’ve found that you can be a bit more generous with the nutmeg than you would salt and pepper in order to get nutmeg flavor to come through.