In this article
- How we ranked the peels and coats
- Food skins high fiber, item by item
- Peels that didn’t make the top eight
- Myth vs fact: the skin is always the best part
- Plant skins nutrition beyond fiber
- Adding the high-fiber skins to your week
- Picking the right skin for you
- Food skins and fiber: questions people ask
- Sources
79 grams. That’s how much fiber USDA lists in 100 grams of crude corn bran, the thin outer coat stripped from corn kernels during milling, and it makes corn bran the top entry on any list of food skins high fiber shoppers can buy.
Grain coats, citrus peels and potato skins all beat the fruit and vegetable flesh they protect. Below, they’re ranked by fiber, with the realistic serving size that tells you what each one adds to your day.
How we ranked the peels and coats
We counted any edible outer layer: the bran around a grain, the peel on fruit, the skin on a tuber and the brown skin on a nut. Fiber values come from USDA FoodData Central, except mango peel, which comes from a published lab analysis.
Each item is ranked by fiber per 100 grams of the skin itself. Because dry bran and fresh peel are eaten in very different amounts, the comparison table also shows a typical serving, worked out from USDA gram weights.
| Rank | Outer layer | Fiber per 100 g | Typical serving | Fiber per serving |
|---|---|---|---|---|
| 1 | Corn bran (crude) | 79.0 g | 1/4 cup, 19 g | about 15 g |
| 2 | Wheat bran (crude) | 42.8 g | 1/4 cup, 14.5 g | about 6.2 g |
| 3 | Mango peel (dried flour) | 40.5 g | not sold as a food | n/a |
| 4 | Rice bran (crude) | 21.0 g | 1/4 cup, 29.5 g | about 6.2 g |
| 5 | Oat bran (raw) | 15.4 g | 1/4 cup, 23.5 g | about 3.6 g |
| 6 | Orange or lemon peel (raw) | 10.6 g | a little zest | well under 1 g |
| 7 | Baked potato skin | 7.9 g | 1 skin, 58 g | 4.6 g |
| 8 | Almond skins | about 2.6 g gained per 100 g of nuts | 1 oz almonds | about 0.7 g |
The almond row works differently: USDA lists natural almonds at 12.5 grams of fiber per 100 grams and blanched almonds, with the skins removed, at 9.9 grams. The gap is what the skins contribute.
Sorted by serving instead of by weight, the order reshuffles. Corn bran still leads at about 15 grams, wheat and rice bran tie near 6 grams, a potato skin follows at 4.6 grams and oat bran lands at 3.6 grams, while zest and almond skins add less than a gram each.
Food skins high fiber, item by item
1. Corn bran
Corn bran is almost pure fiber, with 79 grams per 100 grams and 224 calories. USDA lists a cup at 76 grams, so even a quarter cup brings around 15 grams.
It’s mostly used as an ingredient in baked goods and high-fiber cereals rather than eaten on its own. Its texture is gritty, so small amounts mixed into muffins or pancakes work better than big spoonfuls.
2. Wheat bran
Wheat bran is the outer layer removed when whole wheat is refined into white flour. Mayo Clinic explains that the grain-refining process removes this outer coat, called bran, which is why refined grains are lower in fiber.
USDA lists crude wheat bran at 42.8 grams of fiber per 100 grams, plus 611 mg of magnesium and 10.6 mg of iron. Mayo names wheat bran as a good source of insoluble fiber, the type that adds bulk and helps material move through your gut.
A quarter cup stirred into oatmeal or yogurt gives you about 6 grams, roughly a quarter of a 25 gram daily target.
3. Mango peel
Mango peel is the surprise entry. Researchers who dried and milled unripe Ataulfo mangoes found that the peel flour had 40.5 grams of dietary fiber per 100 grams, more than the flour made from the pulp.
That figure is for dried, ground peel, which isn’t a supermarket food. Fresh mango skin is tough and bitter, so most people won’t eat it, but the research explains why mango peel is being studied as a fiber ingredient.
4. Rice bran
Rice bran is the layer polished off brown rice to make white rice. It has 21 grams of fiber per 100 grams, but also nearly 21 grams of fat, which is why it’s pressed for rice bran oil.
That fat makes rice bran higher in calories than the other brans, at 316 per 100 grams. A small amount goes a long way in baking or smoothies.
5. Oat bran
Oat bran has less total fiber than wheat bran, at 15.4 grams per 100 grams, but it’s one of the best known sources of soluble fiber. Mayo lists oats among the foods rich in this gel-forming type, which helps lower cholesterol and glucose levels.
Oat bran also cooks like a creamy hot cereal, which makes it the easiest bran to eat in a real portion.
Not sure how a spoonful of bran fits your daily target? Our fiber calculator gives you a personal number in seconds.
6. Citrus peel
Raw orange and lemon peel both have 10.6 grams of fiber per 100 grams, and orange peel adds 136 mg of vitamin C. The catch is portion size: you use zest by the pinch, so it flavors food far more than it feeds your fiber total.
Candied peel and marmalade bring a lot of added sugar along with the peel, so they don’t make a good fiber strategy.
7. Baked potato skin
Potato skin is the highest-fiber skin you’re likely to eat in a full portion. USDA lists one baked potato skin at 58 grams, with 4.6 grams of fiber and 332 mg of potassium.
That’s the most practical entry on the list. It needs no special shopping, just a potato cooked in its jacket.
8. Almond skins
The thin brown skin on almonds holds about a fifth of the nut’s fiber. Per ounce, natural almonds have 3.5 grams and blanched almonds 2.8 grams, based on USDA values.
Choosing whole, natural almonds and almond meal over blanched almonds and blanched almond flour keeps that difference on your side.
Peels that didn’t make the top eight
Apple, pear and peach skins are excellent everyday habits, but USDA doesn’t analyze their peels separately, so they can’t be ranked by the same measure. Mayo Clinic notes that removing the skin from fruit lowers its fiber, which is reason enough to keep them on.
Cucumber peel is a low scorer. USDA lists cucumber with peel at just 0.5 grams of fiber per 100 grams, because cucumbers are mostly water.
Onion and garlic skins, banana peels and pineapple rind are left out because they aren’t normally eaten.
Myth vs fact: the skin is always the best part
Myth: the peel is always the most nutritious part of a plant food, so the more skin, the better.
Fact: skins and coats often concentrate fiber, but the ranking depends on how much you can eat. Corn bran tops this list per 100 grams, yet a baked potato skin may do more for your day simply because you’ll eat the whole thing.
Fat and sugar matter too. Rice bran carries nearly as much fat as fiber, and candied citrus peel carries far more sugar than fiber.
Plant skins nutrition beyond fiber
Fiber isn’t the only thing outer layers concentrate. In USDA’s data, wheat bran supplies 611 mg of magnesium and 10.6 mg of iron per 100 grams, and baked potato skin lists 7.0 mg of iron.
| Outer layer (per 100 g) | Fiber | Notable extra |
|---|---|---|
| Wheat bran | 42.8 g | Magnesium 611 mg, iron 10.6 mg |
| Rice bran | 21.0 g | Fat 20.9 g |
| Orange peel | 10.6 g | Vitamin C 136 mg |
| Baked potato skin | 7.9 g | Potassium 573 mg, iron 7.0 mg |
Those extras are part of why whole grains and skin-on produce consistently come out ahead of their refined or peeled versions.
Want more ways to cook with bran, zest and skin-on potatoes? Our recipe eBooks are packed with easy high-fiber ideas.
Adding the high-fiber skins to your week
Start with whatever you already eat. Bake or roast potatoes in their skins, switch from blanched to natural almonds, and zest citrus before you squeeze or peel it.
Then try one bran. A tablespoon or two of wheat or oat bran in your morning bowl is the simplest step, and you can work up to a quarter cup as your gut adjusts.
Bran soaks up liquid, so drink with it. Mayo Clinic advises plenty of water as you add fiber, since fiber works best when it absorbs water and keeps stool soft and easy to pass.
If extra bran tends to leave you bloated, our gut health guides show you how to increase fiber at a comfortable pace.
Picking the right skin for you
If you want the biggest fiber jump in the smallest spoonful, choose corn or wheat bran and mix it into foods you already eat. If you’d rather not buy anything new, keep the skin on potatoes and buy natural almonds instead of blanched.
If cholesterol is your focus, pick oat bran for its soluble fiber. And if you’re after flavor more than fiber, zest is the easy win, just don’t count on it for your daily total.
Food skins and fiber: questions people ask
What food skin has the most fiber?
Corn bran, the outer coat of the corn kernel. USDA lists crude corn bran at 79 grams of fiber per 100 grams, far ahead of any fruit or vegetable peel.
Is bran considered a skin?
In practical terms, yes. Bran is the protective outer coat of a cereal grain, and refining removes it, which is why white flour and white rice have less fiber.
Which fruit peel has the most fiber?
Citrus peel leads among common fruits, with 10.6 grams per 100 grams for raw orange or lemon peel. Dried mango peel has measured higher in lab studies, at 40.5 grams per 100 grams of peel flour.
Do almond skins have fiber?
Yes. Natural almonds have 12.5 grams of fiber per 100 grams and blanched almonds 9.9 grams, so the skins account for about a fifth of the fiber.
How much fiber is in potato skin?
A lot for a vegetable. Baked potato skin has 7.9 grams per 100 grams, and one skin of 58 grams provides 4.6 grams.
Is wheat bran or oat bran better for fiber?
Wheat bran has more total fiber, at 42.8 grams per 100 grams versus 15.4 for oat bran. Oat bran is richer in soluble fiber, which supports healthy cholesterol levels.
Can you eat mango skin?
It’s edible but tough and bitter, so most people don’t. The fiber research on mango peel uses dried, milled peel, not fresh skin.
Sources
- U.S. Department of Agriculture, Agricultural Research Service. “FoodData Central” (corn, wheat, rice and oat bran; orange and lemon peel; baked potato skin; natural and blanched almonds; cucumber). 2019. fdc.nal.usda.gov
- Patiño-Rodríguez O, et al. “Pulp and peel of unripe stenospermocarpic mango (Mangifera indica L. cv Ataulfo) as an alternative source of starch, polyphenols and dietary fibre.” Food Research International. 2020. pubmed.ncbi.nlm.nih.gov
- Mayo Clinic Staff. “Dietary fiber: Essential for a healthy diet.” Mayo Clinic. 2024. mayoclinic.org
