In this article
- Do sweet potatoes have fiber? Grams by portion
- How a cup of sweet potato stacks up
- Sweet potato or white potato: the honest comparison
- Boiled, baked or roasted: why cooking method matters
- Should you eat the skin?
- What the fiber in a sweet potato actually does
- How much fiber in sweet potato fits into your day
- A sweet potato checklist for more fiber
- Picking the right sweet potato for your goal
- Sweet potato fiber FAQs
- Sources
Six point three grams. That’s how much fiber sits in a single cup of cooked sweet potato, according to USDA figures in the Dietary Guidelines for Americans, which puts it ahead of a cup of broccoli or carrots.
So do sweet potatoes have fiber? Yes, and a fair amount. A cup cooked covers about 25% of a 25 gram daily target for 190 calories, while a medium raw sweet potato carries about 4 grams.
Do sweet potatoes have fiber? Grams by portion
Sweet potatoes come in very different sizes, so it helps to see the numbers several ways. The figures below come from the Dietary Guidelines for Americans and the FDA:
| Portion | Fiber | Calories | Share of 25 g target |
|---|---|---|---|
| 1/2 cup cooked | 3.2 g | 95 | 13% |
| 1 medium raw (130 g, about 5 inches long) | 4 g | 100 | 16% |
| 1 cup cooked | 6.3 g | 190 | 25% |
Men aiming for 38 grams a day, the Mayo Clinic target for men 50 and younger, would get a little under a sixth of their goal from that same cup.
A handy rule: a fist sized portion of cooked sweet potato lands around 3 to 4 grams of fiber. Double it as a main dish and you’re past 6 grams.
Are sweet potatoes high in fiber?
By everyday standards, yes. A cup of cooked sweet potato sits near the top of the starchy vegetables, beaten only by green peas in the comparison below.
It also comes with very little effort. There is no soaking, no special prep and no unusual ingredient, just a vegetable most grocery stores stock all year.
How a cup of sweet potato stacks up
This comparison uses the standard portions in the Dietary Guidelines for Americans. Starchy vegetables are grouped together so the calories line up more fairly:
| Vegetable | Portion | Fiber | Calories |
|---|---|---|---|
| Green peas, cooked | 1 cup | 8.8 g | 134 |
| Sweet potato, cooked | 1 cup | 6.3 g | 190 |
| Parsnips, cooked | 1 cup | 6.2 g | 110 |
| Winter squash, cooked | 1 cup | 5.7 g | 76 |
| Broccoli, cooked | 1 cup | 5.2 g | 54 |
| Carrots, cooked | 1 cup | 4.8 g | 54 |
| Corn, cooked | 1 cup | 4.0 g | 134 |
| White potato, baked with skin | 1 medium | 3.9 g | 161 |
Among the starchy options, only green peas beat sweet potatoes on fiber. Next to a baked white potato, a cup of sweet potato brings about 2.4 extra grams.
Lighter vegetables like broccoli and winter squash give you more fiber per calorie. Sweet potatoes win when you want a filling, satisfying carb that still pulls its weight on fiber.
Sweet potato or white potato: the honest comparison
The two often get pitted against each other, and each has a lane. The FDA’s raw vegetable chart lays out the basics for one medium potato of each kind:
| Per medium raw potato | Sweet potato (130 g) | White potato (148 g) |
|---|---|---|
| Calories | 100 | 110 |
| Fiber | 4 g | 2 g |
| Sugars | 7 g | 1 g |
| Potassium | 440 mg | 620 mg |
| Vitamin A | 120% DV | 0% DV |
Sweet potatoes double the fiber and bring a huge dose of vitamin A. White potatoes counter with more potassium and less sugar.
The vitamin A comes from beta carotene, the orange plant pigment your body converts into vitamin A. Harvard’s Nutrition Source notes it’s what gives sweet potatoes their orange or yellow flesh.
Boiled, baked or roasted: why cooking method matters
Myth: sweet potatoes are always gentler on blood sugar than white potatoes.
Fact: it depends heavily on how they’re cooked. Harvard notes that sweet potatoes have only a slightly lower glycemic load than white potatoes, and that large portions of either can still spike blood sugar.
A 2011 study in the Journal of Nutrition and Metabolism tested ten sweet potato varieties prepared four ways and fed them to ten healthy adults. The glycemic index, a 0 to 100 score for how fast a food raises blood sugar, swung widely by method.
| Cooking method | Glycemic index range |
|---|---|
| Boiled | 41 to 50 |
| Roasted | 79 to 93 |
| Baked | 82 to 94 |
Boiled sweet potatoes landed in the low range, while baked and roasted ones scored high. The researchers concluded that preparation method mattered more than the variety.
Baking and roasting break down more of the starch into quickly absorbed sugars, which is part of why oven roasted sweet potatoes taste so sweet. The fiber is still there either way, but the blood sugar response isn’t the same.
If you’re working on steadier energy and fewer afternoon crashes, our gut health guides show how fiber rich meals fit into a calmer daily rhythm.
Should you eat the skin?
You can, and it’s worth it. The skin is edible once scrubbed, and the University of Illinois Extension notes that cooking sweet potatoes with the skin on reduces the loss of beta carotene and vitamin C.
Leaving the skin on also means less work. Wedges, rounds and halved roasted sweet potatoes all hold together better with their jackets intact.
Color varieties add another layer. Illinois Extension notes that orange fleshed sweet potatoes are richest in beta carotene, while purple fleshed ones are richest in anthocyanins, the same family of pigments found in blueberries.
What the fiber in a sweet potato actually does
Fiber comes in two broad types, and whole vegetables like sweet potatoes carry some of each. Mayo Clinic describes how the two behave quite differently once you eat them.
Soluble fiber dissolves in water and forms a gel like material. It can help lower blood cholesterol and glucose levels, which is part of why fiber rich meals digest more slowly.
Insoluble fiber doesn’t dissolve. It adds bulk to stool and helps material move through your digestive system, which can be a real help if you deal with constipation or irregular stools.
Mayo Clinic also links a high fiber diet to a lower risk of heart disease and to easier weight management, because fiber rich foods tend to be more filling and take longer to eat.
That bulk is one reason a bowl of sweet potato feels so satisfying. The fiber slows things down, so the starch and natural sugars reach your bloodstream more gradually than they would from a refined snack with the same calories.
If you’re new to eating this much fiber, Mayo Clinic suggests increasing it gradually over a few weeks and drinking plenty of water. A sudden jump can bring gas, bloating and cramping that fade as your gut adjusts.
How much fiber in sweet potato fits into your day
Mayo Clinic recommends 25 grams of fiber a day for women 50 and younger and 38 grams for men, dropping to 21 and 30 grams after age 50.
One cup of sweet potato at dinner covers a quarter of the smaller target on its own. Pair it with half a cup of black beans (7.5 grams) and a cup of broccoli (5.2 grams), and that single meal tops 19 grams.
Picture a regular weekday built around a sweet potato, using the portions from the Dietary Guidelines for Americans:
- Breakfast: a half cup of cooked sweet potato cubes in a vegetable hash, about 3.2 grams of fiber.
- Lunch: a grain bowl with a cup of cooked lentils, about 7.8 grams.
- Snack: a cup of raspberries, about 8 grams.
- Dinner: a cup of boiled sweet potato with a cup of broccoli, about 11.5 grams.
That adds up to roughly 30 grams without a supplement. The sweet potato appears twice, but neither portion is large, which keeps it from crowding out other vegetables.
Not sure which target applies to you? Our fiber calculator gives you a personal daily number based on your details.
A sweet potato checklist for more fiber
- Scrub the skin and keep it on for roasting, boiling and mashing.
- Boil or steam cubes when blood sugar is a priority, and save roasting for when flavor comes first.
- Mash boiled sweet potato with its skin and a spoon of olive oil instead of butter and brown sugar.
- Fold cooked cubes into black bean chili, grain bowls or a breakfast hash.
- Batch cook a tray at the start of the week so a serving is always ready.
- Try a purple variety now and then for a different set of plant pigments.
Want more ways to work sweet potatoes into breakfasts, bowls and sides? Our recipe eBooks are packed with easy, high fiber meals.
Picking the right sweet potato for your goal
Most of the choice comes down to what you want from the meal:
- If fiber is the goal, any cooking method works, so keep the skin and aim for a full cup.
- If blood sugar is the goal, boil or steam it and pair it with protein and a green vegetable.
- If potassium is the goal, a baked white potato edges ahead, so rotate the two.
- If sweet potato fries are on the menu, treat them like any other fried side, since frying adds fat without adding fiber.
Boiled cubes on a weeknight and roasted wedges on the weekend give you the best of both.
Sweet potato fiber FAQs
How much fiber is in a medium sweet potato?
About 4 grams. The FDA lists a medium raw sweet potato, roughly 5 inches long and 130 grams, at 4 grams of fiber and 100 calories.
Do sweet potatoes have more fiber than regular potatoes?
Yes. A medium sweet potato has about 4 grams of fiber compared with 2 grams in a medium raw white potato, according to the FDA.
Is sweet potato skin good to eat?
Yes, once it’s scrubbed. Cooking with the skin on also helps hold on to beta carotene and vitamin C, according to the University of Illinois Extension.
Does boiling sweet potatoes lower their glycemic index?
Yes. In a 2011 study, boiled sweet potatoes scored 41 to 50 on the glycemic index, while baked ones scored 82 to 94.
Are sweet potatoes good for constipation?
They can help. A cup of cooked sweet potato has 6.3 grams of fiber, and Mayo Clinic recommends adding fiber gradually with plenty of water.
How many grams of fiber are in a cup of mashed sweet potato?
About 6.3 grams per cup of cooked sweet potato, according to the Dietary Guidelines for Americans. Keeping the skin in the mash helps keep the count up.
Are sweet potatoes a good carb for weight loss?
They can be. A cup provides 6.3 grams of fiber for 190 calories, which helps meals feel filling, though portion size still matters.
Sources
- U.S. Department of Agriculture and U.S. Department of Health and Human Services. “Food Sources of Dietary Fiber.” Dietary Guidelines for Americans, 2020 to 2025. dietaryguidelines.gov
- U.S. Food and Drug Administration. “Nutrition Information for Raw Vegetables.” 2017. www.fda.gov
- Harvard T.H. Chan School of Public Health. “Potatoes.” The Nutrition Source. 2025. nutritionsource.hsph.harvard.edu
- Bahado-Singh PS, Riley CK, Wheatley AO, Lowe HIC. Journal of Nutrition and Metabolism. “Relationship between Processing Method and the Glycemic Indices of Ten Sweet Potato (Ipomoea batatas) Cultivars Commonly Consumed in Jamaica.” 2011. pmc.ncbi.nlm.nih.gov
- University of Illinois Extension. “The power of sweet potatoes.” 2024. extension.illinois.edu
- Mayo Clinic. “Dietary fiber: Essential for a healthy diet.” 2025. www.mayoclinic.org
