Resistant Maltodextrin vs. Maltodextrin: Same Name, Opposite Job
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Last updated October 7, 2026 · By the Fiber Society team
Regular maltodextrin and resistant maltodextrin share a name but do opposite jobs. Maltodextrin is a quickly digested starch that your body breaks down to glucose and absorbs about as fast as glucose itself. Resistant maltodextrin (sold as Fibersol-2 or "soluble corn fiber") is processed so that most of it is not digested, which is why FDA counts it as a dietary fiber on the Nutrition Facts label.
Key takeaways
- Maltodextrin is a digestible starch made by partially breaking down corn, potato, or rice starch. It is labeled at 4 calories per gram and is not a fiber.
- Resistant maltodextrin is corn starch treated with heat, acid, and enzymes, which creates glucose linkages human enzymes cannot cut. About 90% of it reaches the colon.
- FDA lists "resistant maltodextrin/dextrin" among the carbohydrates that meet its dietary fiber definition and labels soluble non-digestible carbohydrates at 2 calories per gram.
- It dissolves fully with low viscosity and ferments slowly and partially. Studies at 15 to 25 g a day for three weeks reported it was well tolerated.
- Fiber Society's Daily Fiber Blend uses 1.95 g of Fibersol-2 per scoop alongside acacia and psyllium because it is soluble, thin in water, and mild in taste.
Why is there maltodextrin in a fiber supplement?
If you have read that maltodextrin spikes blood sugar, seeing "resistant maltodextrin" on a fiber label can look like a contradiction.
The key word is resistant. Regular maltodextrin and resistant maltodextrin are different ingredients with different chemistry. One is built to be digested quickly; the other is built so that digestive enzymes mostly cannot touch it. Here is what each one is, how FDA treats them, and what the research says.
What regular maltodextrin is
FDA's food additive regulation (21 CFR 184.1444) describes maltodextrin as a "nonsweet nutritive saccharide polymer" made of D-glucose units linked mainly by alpha-1,4 bonds, with a dextrose equivalent below 20, produced by partially hydrolyzing corn, potato, or rice starch with acids and enzymes.
"Nutritive" is the important word. Alpha-1,4 bonds are exactly what your digestive enzymes are built to break. A 2016 review in Critical Reviews in Food Science and Nutrition concluded that digestible maltodextrins are broken down at a high rate, with an absorption rate "not being different from absorption after ingestion of pure glucose." Glucose is the reference food for the glycemic index; the 2008 international GI tables list it at 103 plus or minus 3 across studies, the top of the scale.
On a Nutrition Facts label, maltodextrin is counted inside total carbohydrate at 4 calories per gram. It is used as a bulking agent, a flavor carrier, and a fast carbohydrate in sports drinks. It is not a fiber.
What resistant maltodextrin is (Fibersol-2, soluble corn fiber)
How resistant maltodextrin is made
Resistant maltodextrin starts with the same raw material, corn starch, but goes through an extra step. A 2016 clinical paper in the European Journal of Nutrition describes the process as hydrolysis with heat and hydrochloric acid under low humidity, then hydrolysis with amylase, followed by refining and spray-drying.
The heat-and-acid step rearranges some glucose-to-glucose bonds. FDA's 2018 scientific review describes the result as glucose oligosaccharides joined by digestible linkages plus non-digestible alpha-1,2 and alpha-1,3 linkages. Human enzymes do not recognize those bonds, so most of the molecule passes through the small intestine intact. In lab digestion tests, resistant maltodextrins hydrolyzed less than 8%, with viscosity close to negligible compared with native starch.
What it is called on labels
Fibersol-2 is a brand name for a resistant maltodextrin made from corn. FDA's review notes that common ingredient names include soluble corn fiber, resistant dextrin, resistant wheat dextrin, soluble wheat fiber, and wheat dextrin. Any of these means the same family of fiber, not regular maltodextrin.
Does FDA count resistant maltodextrin as dietary fiber?
Yes. FDA defines dietary fiber as non-digestible soluble and insoluble carbohydrates (with 3 or more monomeric units) that are either intrinsic in plants or isolated and shown to have a beneficial physiological effect. Its published list of isolated carbohydrates that meet that definition includes "resistant maltodextrin/dextrin" alongside acacia (gum arabic), psyllium husk, inulin, and polydextrose.
FDA's June 2018 review found that resistant maltodextrin increased calcium absorption and retention in human stable-isotope studies at 10 to 20 g per day, the beneficial effect that qualified it. Under 21 CFR 101.9, soluble non-digestible carbohydrates are labeled at 2 calories per gram rather than 4.
Resistant maltodextrin vs maltodextrin: side by side
| Feature | Maltodextrin | Resistant maltodextrin (Fibersol-2) |
|---|---|---|
| What it is | Digestible glucose polymer, mostly alpha-1,4 bonds, dextrose equivalent under 20 | Glucose oligosaccharide with added non-digestible alpha-1,2 and alpha-1,3 bonds |
| How it is made | Partial hydrolysis of corn, potato, or rice starch with acids and enzymes | Corn starch treated with heat and acid, then amylase, then refined and spray-dried |
| Digestibility | Broken down to glucose at a rate similar to pure glucose | Roughly 10% digested in the small intestine; about 90% reaches the colon |
| Calories per gram (FDA labeling) | 4 (general carbohydrate factor) | 2 (soluble non-digestible carbohydrate factor) |
| Dietary fiber status | No; counted as total carbohydrate | Yes; on FDA's list of fibers that meet the definition |
| Fermentation | Not applicable; absorbed before reaching the colon | Partial and slow; shifts short-chain fatty acids toward butyrate |
| Texture in water | Dissolves; nonsweet | Fully soluble with low viscosity; thin in liquids |
| Typical use | Bulking agent, flavor carrier, sports-drink carbohydrate | Added fiber in beverages, bars, cereals, and fiber supplements |
How resistant maltodextrin behaves in the gut
Slow, partial fermentation
Fiber that reaches the colon is fermented by gut bacteria, and how fast that happens matters for comfort. Inulin-type fibers ferment quickly. Resistant maltodextrin is described in the clinical literature as fermenting at a slow and steady rate, slower than inulin-type fructans. For the longer comparison, see psyllium vs inulin.
In the Fastinger 2008 study, 38 healthy adults took 15 g a day of regular maltodextrin, Fibersol-2, or a half-and-half mix for three weeks. The resistant maltodextrin "resulted in very minor effects in gastrointestinal tolerance," shifted short-chain fatty acid proportions toward butyrate, and tended to increase fecal Bifidobacterium counts.
Because fermentation is partial, the fiber still yields some energy. A 2014 Journal of Nutrition crossover study in 14 men measured the metabolizable energy of resistant maltodextrin at 8.2 kJ/g (about 2 kcal/g) at 25 g a day and 10.4 kJ/g (about 2.5 kcal/g) at 50 g a day, in line with FDA's 2 calories per gram labeling factor.
Doses used in studies and how they were tolerated
- 10 to 20 g a day, 3 to 7 weeks: the calcium-absorption studies in adolescents and postmenopausal women reviewed by FDA.
- 15 g a day, 21 days: 66 healthy adults in a placebo-controlled trial; the authors reported no adverse effects related to the study products.
- 15 and 25 g a day, 3 weeks each: 51 healthy adults in a crossover trial; 25 g raised stool wet weight from 121 to 150 g a day and increased bifidobacteria versus placebo.
- Single large doses: in 10 adults, no diarrhea occurred at single doses of 0.7 to 1.0 g per kg of body weight (about 70 g for a 70 kg man). Some noticed mild, temporary gurgling and gas.
These are much larger amounts than a typical scoop of fiber powder provides, and even then the reported side effects were the mild, transient kind you would expect from any fermentable fiber. Our article on why fiber makes you bloated explains how to ramp up comfortably.
Is resistant maltodextrin bad for you?
The worry usually comes from mixing up the two ingredients. Regular maltodextrin behaves like glucose: fast digestion, fast absorption, 4 calories per gram. Resistant maltodextrin is built so that most of it is not digested, which is why FDA lists it as a dietary fiber.
In the human studies above, 15 to 25 g a day for three weeks was well tolerated. Like every fermentable fiber, it can produce some gas while your gut adjusts, so introduce it gradually, and check with your healthcare provider if you have a digestive condition or take medication.
Where Fiber Society fits
Fiber Society's Daily Fiber Blend (Strawberry Lemonade) delivers 10 g of dietary fiber per 14.2 g scoop from four sources: 7.3 g organic acacia (gum arabic), 2.5 g psyllium husk, 1.95 g Fibersol-2 (resistant maltodextrin, soluble corn fiber), and 300 mg BeniCaros carrot-derived RG-I fiber. Each scoop has about 20 calories, 0 g total sugars, and 0 g added sugars, and is sweetened with stevia (Reb M). It is vegan and gluten-free, with no synthetic dyes.
Fibersol-2 earns its place for the reasons it shows up in the studies above: it is fully soluble, low in viscosity, and mild in taste, so it adds fiber without adding thickness or flavor. Because most of the fiber is acacia and psyllium is kept to 2.5 g, the drink is designed to be thin in 12 to 14 fl oz of cold water. It supports regularity and digestive health* and is gentle by design; start with half a scoop for the first few days. For how the two main fibers compare, read acacia vs psyllium.
Frequently asked questions
Is maltodextrin a fiber?
No. Regular maltodextrin is a digestible starch that FDA describes as a "nutritive" saccharide polymer. It is counted inside total carbohydrate at 4 calories per gram and is not on FDA's list of dietary fibers.
What is Fibersol-2?
Fibersol-2 is a brand name for a resistant maltodextrin made from corn starch using heat, acid, and enzyme treatment. It is a soluble, low-viscosity dietary fiber that FDA recognizes under the category "resistant maltodextrin/dextrin."
Is soluble corn fiber the same as resistant maltodextrin?
Generally, yes. FDA's 2018 review lists soluble corn fiber as a common ingredient name for resistant maltodextrin, along with resistant dextrin and wheat dextrin. The label name depends on the starch source and the manufacturer.
How many calories does resistant maltodextrin have?
FDA labels soluble non-digestible carbohydrates at 2 calories per gram. A human metabolizable-energy study measured about 2 to 2.5 kcal per gram depending on dose, versus 4 kcal per gram for regular maltodextrin.
Does resistant maltodextrin cause gas?
Any fermentable fiber can, especially at first. In a three-week trial at 15 g a day, researchers reported only very minor effects on gastrointestinal tolerance, and the mild gurgling and gas in a single-dose study occurred at amounts far above what a fiber supplement provides. Ramping up slowly helps. See soluble vs insoluble fiber for how different fibers behave.
Sources
- FDA. Questions and Answers on Dietary Fiber.
- FDA. Review of the Scientific Evidence on the Physiological Effects of Certain Non-Digestible Carbohydrates. June 2018.
- 21 CFR 101.9, Nutrition labeling of food.
- 21 CFR 184.1444, Maltodextrin.
- Hofman DL, et al. Nutrition, health, and regulatory aspects of digestible maltodextrins. Crit Rev Food Sci Nutr. 2016;56(12):2091-2100.
- Atkinson FS, et al. International tables of glycemic index and glycemic load values: 2008. Diabetes Care. 2008;31(12):2281-2283.
- Fastinger ND, et al. A novel resistant maltodextrin alters gastrointestinal tolerance factors, fecal characteristics, and fecal microbiota in healthy adult humans. J Am Coll Nutr. 2008;27(2):356-366.
- Abellan Ruiz MS, et al. Digestion-resistant maltodextrin effects on colonic transit time and stool weight. Eur J Nutr. 2016;55(8):2389-2397.
- Burns AM, et al. In healthy adults, resistant maltodextrin produces a greater change in fecal bifidobacteria counts and increases stool wet weight. Nutr Res. 2018;60:33-42.
- Baer DJ, et al. The metabolizable energy of dietary resistant maltodextrin is variable and alters fecal microbiota composition in adult men. J Nutr. 2014;144(7):1023-1029.
- Kishimoto Y, et al. The maximum single dose of resistant maltodextrin that does not cause diarrhea in humans. J Nutr Sci Vitaminol. 2013;59(4):352-357.
- Shahid ASMSB, et al. Digestive tolerability and acceptability of Fibersol-2 in healthy and diarrheal children 1-3 years old. PLoS One. 2022;17(9):e0274302.
- Chen X, et al. A comparative study of resistant dextrins and resistant maltodextrins from different tuber crop starches. Polymers. 2023;15(23):4545.
This article is for general education and isn't medical advice. Talk to your healthcare provider about your own needs, especially if you take medication or have a digestive condition.
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.