Ingredient file // Fiber
Potato Fiber
A fermentable starch-plant fiber, not a calorie-free one
Potato fiber is the pulp left after a starch plant washes the starch out of potatoes. In kibble it adds fiber that colon bacteria ferment, but it still carries starch, and the dog evidence rests on one small trial.
- What it is
- The dried pulp left once starch is washed out of potatoes: plant cell walls plus some leftover starch.
- Made from
- Potatoes processed at starch plants
- Main job
- Fiber for stool and fermentation
- Typical amount
- A few percent; the one dog trial fed 1.5 to 6%
- Watch for
- Dogs with a diagnosed potato allergy
- Not the same as
- Potatoes or potato starch
Straight answer
Is Potato Fiber safe for dogs?
Count it as fiber, then add up the potatoes
Potato fiber belongs low in the list, where a few percent does its job. Read it with the potato, sweet potato and pulse lines around it, since together they show how starchy the recipe is. Ignore any prebiotic promise beyond what one 10-dog trial showed.
- Why it is in the food
- Fiber for stool and fermentation
- How common
- Listed by 1 of the 3,205 foods we track
Our read // In our catalog
In 1 of every 3,205 foods we track
Share of foods that list it
<1%
1 of the 3,205 foods with an ingredient list on file, from 1 brand. All dry dog food.
Each square is 1% of the catalog
Where it sits on the label
Median position 10. In the top five of 0 foods, so it is usually a supporting ingredient.
Above the salt
Almost always listed before the salt, so there is more of it than a pinch.
Price per lb
Median of the cheapest bag price across 1 priced foods, 35% below the catalog. The price is the food's, not the ingredient's.
Who leans on it
100%
of the foods that list it are from Taste of the Wild. 1 brand use it in total.
What it is
How it is made
Potato fiber comes from the potato starch industry. Plants grind potatoes and wash the starch out to sell as starch. The cell-wall pulp left behind is dried and sold as a fiber ingredient.2,3,4
- 01 // Source Starch potatoes Whole potatoes go to a starch plant, where 100 kg of tubers yields 16 to 20 kg of starch.
- 02 // Process Rasped and washed The tubers are rasped and washed in cold water so the starch flows out of the broken cells.
- 03 // Process Pulp held back What stays behind is pulp: cellulose, hemicellulose and pectin, plus starch that did not wash out.
- 04 // Process Dried The wet pulp is dried. Every 100 kg of potatoes leaves only 3 to 3.5 kg of dried pulp.
- 05 // Output Potato fiber A dry powder averaging about 87% dry matter, shipped to food and pet food plants.
What is in it
Composition, dry matter
44
% starch
Average starch in dried potato pulp, against about 19% crude fiber. It is sold as fiber but still brings starch and calories.
Why it is in the bag
What the manufacturer gets
-
01
Insoluble fiber for the stool
About 32% of the trial fiber was insoluble, mostly cellulose and hemicellulose, the kind that holds water in the colon. Stool characteristics held at every level fed.1,2
-
02
Feeds colon bacteria
About 23% is soluble fiber, mainly pectin. Dog fecal bacteria fermented it for 9 hours in the lab, and fecal short-chain fatty acids rose in fed dogs.1,2
-
03
A by-product with feed value
Starch makers are left with 3 to 3.5 kg of dried pulp per 100 kg of potatoes, a by-product Feedipedia calls an environmental threat as well as very valuable for animal feeding.3
How much The one dog trial fed it at 1.5, 3, 4.5 and 6% of the diet as fed, with no loss of digestibility or stool quality.1,2
Our read // The claims
What the evidence supports
Strong: controlled studies in dogs agree. Some: small or mixed dog data. Thin: mechanism or lab work only. None: nothing, or the evidence points the other way.
-
Brands say
Adds fiber without hurting digestion or stool
Evidence
- Strong
- Some
- Thin
- None
In a 10-dog Latin square trial at up to 6%, digestibility of dry matter, protein, fat and energy did not change and stools held. It is one small trial, funded by the fiber's maker.1,2
-
Brands say
A prebiotic fiber that feeds good gut bacteria
Outruns the evidence
Evidence
- Strong
- Some
- Thin
- None
In a 10-dog, maker-funded trial, short-chain fatty acids rose and Faecalibacterium increased, but Lactobacillus and Bifidobacterium did not change by qPCR, and no health outcome was measured. The study authors call it only a possible prebiotic.1,2
-
Brands say
Adds bulk without adding calories
Outruns the evidence
Evidence
- Strong
- Some
- Thin
- None
Dried potato pulp averages 44% starch on a dry basis, and the trial fiber still held 29% starch. It brings fewer calories than potato, not none.1,4
-
Critics say
Potatoes in grain-free food cause heart disease
Outruns the evidence
Evidence
- Strong
- Some
- Thin
- None
FDA found potatoes or sweet potatoes in 42% of products named in DCM reports, a far smaller share than peas, and says reports alone cannot show cause. Those counts describe whole recipes, not potato fiber.5
Straight answers
What owners ask
-
Q01
Is it just filler?
No, it's fiberAbout half of it is dietary fiber: insoluble cellulose and hemicellulose, plus pectin. In a 10-dog trial, bacteria fermented it and short-chain fatty acids rose, with stool and digestibility unharmed. Its bulking role is inferred from the insoluble fiber, not measured.1,2
-
Q02
Is it the same as potatoes?
NoPotatoes are mostly starch. Potato fiber is what remains after most of that starch is washed out, only 3 to 3.5 kg of dried pulp per 100 kg of potatoes, though some starch stays.3,4
-
Q03
Should I avoid it over DCM?
Not by defaultFDA's DCM reports pointed far more to peas than potatoes, and cannot show cause. A few percent of potato fiber is not the pattern under question. Dogs already diagnosed are a different case.5
Who uses it
Brands, best sellers and the company it keeps
Top brands, by foods that list it
Foods that list it / all the brand's recipes we track.
Usually listed with, share of the foods that list it
- Salmon 100%
- Ocean Fish Meal 100%
- Sweet Potatoes 100%
- Potatoes 100%
- Peas 100%
- Canola Oil 100%
- Mixed Tocopherols 100%
- Lentils 100%
- Salmon Meal 100%
- Smoked Salmon 100%
On the shelf
Foods that list Potato Fiber
1 food in our catalog lists it, highest on the label first.
Sources
What we read
Checked October 24, 2026.
- 1 Potato fiber as a dietary fiber source in dog foods
- 2 Modulation of the faecal microbiome of healthy adult dogs by inclusion of potato fibre in the diet
- 3 Potato (Solanum tuberosum) by-products
- 4 Potato pulp, dehydrated
- 5 FDA Investigation into Potential Link between Certain Diets and Canine Dilated Cardiomyopathy