Last verified 16 Sep 2026 · Sources
Dietary fiber on a Nutrition Facts panel means two things, and only two things: fiber that’s naturally built into the plant material itself, and a specific, FDA-reviewed list of isolated or synthetic fibers added during manufacturing. That definition, adopted in the 2016 nutrition-labeling final rule, replaced an older “any non-digestible carbohydrate” standard that let manufacturers count fiber-like additives FDA had never evaluated for a health benefit. The Daily Value is 28 g, declared to the nearest gram, and the soluble/insoluble breakdown remains voluntary.
| Quick facts | Dietary Fiber |
|---|---|
| Regulation | 21 CFR 101.9(c)(6)(i) |
| Applies to | Any packaged food with a Nutrition Facts panel that contains fiber |
| Key numbers | Dietary fiber DV: 28g; declared to the nearest gram; only FDA-recognized isolated fibers count |
The rule
21 CFR 101.9(c)(6)(i) defines dietary fiber as “non-digestible soluble and insoluble carbohydrates (with 3 or more monomeric units), and lignin that are intrinsic and intact in plants; isolated or synthetic non-digestible carbohydrates (with 3 or more monomeric units) determined by FDA to have physiological effects that are beneficial to human health.” The first half of that definition, “intrinsic and intact,” covers fiber as it naturally occurs in whole or minimally processed plant ingredients: the bran in whole wheat, the pectin structure in an apple, the cell walls in oats. It does not require any FDA review; it’s simply what’s already there.
The second half is where the 2016 rule changed the standard. Before then, food companies could add almost any non-digestible carbohydrate (certain isolated fibers, resistant starches, functional additives) and count the grams as dietary fiber even without evidence the ingredient did anything for the person eating it. The 2016 rule requires FDA to determine, ingredient by ingredient, that an isolated or synthetic fiber has a beneficial physiological effect (things like lowering blood glucose or cholesterol, or increasing satiety) before its grams can count. FDA maintains that list and updates it through its “Questions and Answers on Dietary Fiber” guidance and related citizen petition responses (fda.gov/food/food-labeling-nutrition/questions-and-answers-dietary-fiber).
An isolated fiber not on that list, even one that behaves like fiber in a lab test, cannot be declared as dietary fiber grams; it has to be counted as another form of carbohydrate instead. This is why two products with the same ingredient panel can show different declared fiber depending on which specific fiber source and form they use.
The numbers
- Daily Value: 28 g, for adults and children 4 years and older (21 CFR 101.9(c)(9)).
- Declaration: to the nearest gram; below 1 gram, may be stated as “less than 1 gram” or as zero, following the same convention used for total carbohydrate.
- %DV: calculated against the 28 g DV, rounded to the nearest whole percent under (d)(7)(ii).
- Soluble/insoluble fiber: voluntary subdivision; not required on any label format.
- FDA-recognized isolated/synthetic fibers: FDA has recognized fibers including beta-glucan soluble fiber, psyllium husk, cellulose, guar gum, pectin, locust bean gum, hydroxypropylmethylcellulose, and, by later determination, inulin and inulin-type fructans and resistant maltodextrin/dextrin, among others. Check FDA’s “Questions and Answers on Dietary Fiber” page for the current list rather than treating this as a fixed count.
On the label
A loaf of bread made with whole wheat flour and no added fiber ingredients declares dietary fiber based only on what’s intrinsic to the wheat itself, with no FDA list-checking required, because nothing isolated was added. If you make a granola bar with an added isolated fiber, by contrast, you only get to count those grams if that specific fiber source is on FDA’s reviewed list; if you used an isolated fiber FDA hasn’t evaluated, those grams have to move into the “total carbohydrate” bucket instead of the “dietary fiber” line, which also lowers the fiber %DV your label can claim.
Mistakes we see
- Counting grams from an added isolated fiber that isn’t on FDA’s reviewed list, inflating the dietary fiber declaration.
- Assuming any ingredient marketed as “fiber” by a supplier automatically qualifies for the Nutrition Facts fiber line.
- Breaking out soluble and insoluble fiber on the panel when only total fiber is required, adding clutter without a compliance need.
- Using an outdated fiber DV (the pre-2016 rule used 25 g) instead of the current 28 g.
- Failing to re-check a supplier’s fiber ingredient against FDA’s list after a recipe reformulation.
Related rules
Dietary fiber’s 28 g Daily Value is calculated the same way as other macronutrient %DV figures; see Percent Daily Value for the rounding rule that applies. If your product claims “good source of fiber” or “high fiber” on the front of pack, check nutrient content claims for the gram thresholds those terms require. Bakery and grain-based products bumping up fiber often add sugar or sugar alcohols to balance texture, so also see added sugars and sugar alcohols for how those lines interact on the same panel.
Build it right, automatically
NutriLabels’ builder tracks which isolated fibers FDA currently recognizes and calculates your dietary fiber grams and %DV against the 28 g Daily Value automatically, so a reformulation doesn’t accidentally overstate your fiber line.
A fiber number you can back up holds steady when a retailer or inspector asks where it came from. Enter your recipe, then see your label: the calorie count, the nutrient content claims you qualify for and your allergen line show free, no card required, while every other value and %DV stays hidden until you unlock it. $29 unlocks every other nutrient value and %DV, every FDA format your product qualifies for, and your ingredient statement and allergen declaration, ready to print. Start your label or check the nutrient content claims thresholds for fiber.
FAQ
What is FDA's definition of dietary fiber?
Non-digestible soluble and insoluble carbohydrates (three or more monomeric units) and lignin that are intrinsic and intact in plants, plus isolated or synthetic non-digestible carbohydrates FDA has determined have a beneficial physiological effect, per 21 CFR 101.9(c)(6)(i).
Can I count any fiber-like ingredient toward dietary fiber?
No. Only fiber that is intrinsic and intact in the plant material itself, or an isolated/synthetic fiber on FDA's reviewed list, counts toward the declared grams.
What is the Daily Value for fiber?
28 grams for adults and children 4 and up, per 21 CFR 101.9(c)(9).
Does a label have to break fiber into soluble and insoluble?
No, that breakdown is voluntary; only total dietary fiber is mandatory on the panel.
How many isolated fibers has FDA recognized?
FDA maintains the current list on its 'Questions and Answers on Dietary Fiber' page rather than publishing a fixed count, and it periodically adds substances through citizen-petition decisions, so check that page for what's currently recognized rather than relying on a number.
Related rules
Added Sugars, Percent Daily Value (%DV), Rounding rules, Nutrient content claims. See the full all labeling rules.