How Much Dietary Fiber Is in a Sweet Potato? Soluble vs. Insoluble
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A medium sweet potato, about 130 grams baked with the skin on, contains roughly 4 grams of dietary fiber. That answers how much dietary fiber in a sweet potato for the most common size, and it works out to around 14% of the 28 gram daily value used on nutrition labels. What makes sweet potato interesting is not just the total number but the split, because it carries both soluble and insoluble fiber rather than leaning heavily on one type.
Dietary Fiber by Size and Preparation
Fiber in a sweet potato scales almost entirely with weight. Bigger root, more fiber. The skin adds a meaningful share, and how you cook it changes the water content more than the fiber itself. Boiling can leach a small amount of soluble fiber into the cooking water, while baking and roasting concentrate everything as moisture evaporates.
| Portion | Approx. weight | Dietary fiber | % Daily value (28g) |
|---|---|---|---|
| Small, baked with skin | 60 g | ~1.8 g | 6% |
| Medium, baked with skin | 130 g | ~3.8 g | 14% |
| Medium, baked, skin removed | 115 g | ~3.1 g | 11% |
| Large, baked with skin | 180 g | ~5.3 g | 19% |
| 1 cup mashed, no skin | 255 g | ~6.6 g | 24% |
| 1 cup cubed, boiled | 200 g | ~5.0 g | 18% |
Numbers are averages across common orange varieties. Purple, white, and Japanese types land in a similar range, with modest differences by cultivar and growing conditions.
Soluble vs. Insoluble Fiber in Sweet Potato
Dietary fiber is an umbrella term for plant carbohydrates your small intestine does not digest. Sweet potato carries both major categories, which is part of why it shows up so often in lists of fiber-forward vegetables.
Soluble fiber
Roughly 15 to 20 percent of the fiber in a sweet potato is soluble, largely pectin. Soluble fiber dissolves in water and forms a gel-like texture, which is part of why cooked sweet potato mashes so smoothly compared with a starchy russet.
Insoluble fiber
The remaining majority is insoluble fiber, mostly cellulose and hemicellulose concentrated in the skin and the fibrous strands just beneath it. This is the structural material of the root, and it does not dissolve or soften much during cooking.
Why the Skin Matters More Than You Think
Peeling a medium sweet potato removes somewhere between 0.5 and 1 gram of fiber, which is a fifth or more of the total. The skin is thin, edible, and holds a disproportionate amount of the insoluble fraction. If you are eating sweet potato specifically for fiber, leaving the skin on is the single easiest way to get more of it without changing portion size. There is more detail on texture and prep in our guide to eating sweet potato skin.
Products made from peeled, pureed sweet potato, like many canned varieties and some purees, land on the lower end of the fiber range for the same weight.
How Sweet Potato Compares to Other Fiber Sources
Four grams from one medium vegetable is solid but not extraordinary. Beans and lentils outpace it easily. Where sweet potato stands out is density per calorie combined with the fact that most people will actually eat a whole one, which is not always true of a cup of split peas.
| Food | Serving | Dietary fiber |
|---|---|---|
| Sweet potato, baked with skin | 1 medium | ~3.8 g |
| White potato, baked with skin | 1 medium | ~3.6 g |
| Black beans, cooked | 1/2 cup | ~7.5 g |
| Broccoli, cooked | 1 cup | ~5.1 g |
| Apple with skin | 1 medium | ~4.4 g |
| Brown rice, cooked | 1 cup | ~3.5 g |
For the full picture of carbs, protein, and fat alongside fiber, see our breakdown of sweet potato macros, or start with the complete sweet potato guide if you want the whole vegetable covered in one place.
Hitting Your Daily Fiber Target
General guidance puts adult fiber intake around 25 grams per day for women and 38 grams for men, with the 28 gram daily value used for labeling. Most people in the United States fall well short of that. A medium sweet potato covers a meaningful slice of the gap, but it is one contributor among many, and variety across vegetables, fruits, legumes, nuts, and whole grains matters more than any single food. If you have a specific fiber target tied to a health condition or a nutrition goal, talk with your doctor or a registered dietitian about what makes sense for you.
One practical note: increasing fiber quickly can feel uncomfortable. Ramping up gradually and drinking enough water tends to go better than a sudden jump.
Frequently Asked Questions
Does cooking destroy the fiber in sweet potato?
No. Fiber is heat stable, so baking, boiling, steaming, and air frying do not meaningfully reduce the total. Boiling can move a small amount of soluble fiber into the water, and cooking softens texture, but the gram count per 100 grams of cooked flesh stays close to raw.
Is there more fiber in a raw or cooked sweet potato?
Per 100 grams, a baked sweet potato often shows slightly more fiber than raw simply because water has evaporated and everything is concentrated. Compare the same whole potato before and after cooking and the total fiber is essentially unchanged.
Do purple and Japanese sweet potatoes have more fiber?
They are broadly comparable to orange varieties, usually landing in the 3 to 4.5 gram range for a medium root with skin. Differences between individual potatoes of the same variety are often as large as differences between varieties.
How much fiber is in dried sweet potato?
Drying removes water, so the fiber concentrates by weight. A 40 gram serving of dried sweet potato can deliver a similar amount of fiber to a much larger fresh portion, which is why dried sweet potato snacks tend to show respectable fiber numbers on the label.
Do sweet potato fries and chips count toward fiber?
They contribute some, though peeling and thin cuts reduce it, and deep frying adds fat and calories that change the overall profile. Reading the actual label beats assuming, since preparation varies widely between brands.
An Easier Way to Get Sweet Potato Fiber
Baking a sweet potato takes 45 minutes and a fork. That is fine at home and useless at 3 p.m. at your desk. Yammy sweet potato sticks are made from real sweet potato and never deep-fried, with 4 grams of fiber and 3 grams of protein per serving. They are chewy like a fruit leather rather than crunchy, and they are naturally vegan and gluten-free. The Original, Salt & Pepper, and Sriracha flavors have no added sugar.
If you want the fiber from a real vegetable without the oven, browse the full lineup of Yammy sweet potato sticks and pick a flavor.