Fiber Sweetener | Buying Guide

SWEET SOLUBLE FIBERS

2025 BUYING GUIDE

In my quest to help home cooks find sugar alternatives that deliver both sweetness and potential health benefits, I introduce sweet soluble fibers—the best of both worlds. Welcome to your guide!

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WHAT ARE SWEET SOLUBLE FIBERS?

Sweet soluble fibers are mildly sweet carbohydrates that bypass digestion in the small intestine, providing fewer calories than sugar. They are called ‘soluble’ because they dissolve in water, forming a gel-like consistency in the digestive system.

They consist of short chains (oligomers) or long chains (polymers) of fructose or glucose. While they’re not zero-calorie sweeteners, they offer about 50% fewer calories than sugar, allowing them to be labeled as reduced-calorie sweeteners.

Soluble fibers are valued for their digestive benefits, working in two ways:
• as prebiotics, stimulating the growth and activity of gut microbes
• as a fiber, improving bowel function.

But their benefits don’t stop there—they may also contribute to overall health in several other ways.

For home cooks, soluble fibers help lighten up recipes while keeping sugar-like texture. As bulk sweeteners, they do more than just add sweetness. They also add weight and volume, while helping to thicken, bind ingredients, and make them viscous or creamy. This sets soluble fibers apart from bulk-free sweeteners, which are highly concentrated and used solely for sweetness.

TYPES OF SWEET SOLUBLE FIBERS

Sweet soluble fibers fall under a category of food ingredients that the FDA classifies as dietary fibers. They consist of non-digestible carbohydrates that can be either isolated (extracted directly from plants) or synthetic (produced through fermentation, chemical or enzymatic processes).

To be recognized as dietary fiber, they must demonstrate beneficial physiological effects. Dietary fibers used as sweeteners include:

Inulin
Inulin is a mixture of short and long chains of (2 to 60) fructose molecules. It's typically extracted from Jerusalem artichoke, chicory root, or agave. Chicory root inulin, imported from Europe, tends to be the most widely available and cost-effective. Agave inulin is imported from Mexico. Inulin can also be produced enzymatically from sugar cane.
Fructo-oligosaccharides (FOS)
Fructooligosaccharides (FOS), also known as oligofructose, are linear chains of fewer than 9 fructose molecules. FOS are present in yacon syrup, yacon powder, and can be made from inulin.

You'll also see FOS listed as chicory root fiber on the label of sugar alternatives. However, not all chicory root fiber is pure FOS—some products contain a mix of inulin and FOS since both are naturally present in chicory root.

Yacon sweeteners
Yacon syrup and powder are not pure soluble fibers; instead, they are a blend of FOS and sugars (fructose, glucose, sucrose). They are extracted from the root of yacon, a plant native to Peru, that resembles a sweet potato and is naturally rich in FOS. Yacon syrup and powder are made from its extracted juice and are imported from Peru. Yacon syrup has a dark color and consistency similar to cane molasses.

Soluble Tapioca Fiber
Soluble tapioca fiber, also labeled as resistant dextrin or soluble fiber from tapioca, is derived from cassava root. It’s a synthetic fiber made by enzymatically breaking down starch into shorter chains, which are then chemically modified to resist digestion. Even though it's not actually a fiber, it functions like one.

Unlike inulin and FOS, which are composed of fructose molecules, soluble tapioca fiber consists primarily of glucose units. Soluble tapioca fiber is recognized by the FDA as a dietary fiber, depending on the specific type and processing.

IMO or Isomalto-oligosaccharides

Another soluble fiber used as a sweetener, known as IMO, is made up of short chains of glucose molecules also derived from tapioca (cassava) starch. However, after evaluating the scientific evidence, the FDA concluded that IMOs do not demonstrate a beneficial physiological effect on human health.

Unlike true dietary fibers, some of the glucose chains in IMO are broken down by digestive enzymes and absorbed, leading to a blood sugar response. As a result, IMOs are not recognized as dietary fiber under FDA regulations.

How sweet are sweet soluble fibers?

The sweetness of soluble fibers ranges from very mild to mild:

Inulin – Slightly sweet, 10 to 30% as sweet as sugar
FOS and IMO – 30 to 65% as sweet as sugar
Yacon sweeteners – About 70% as sweet than sugar
Soluble tapioca fiber – 20 to 30% as sweet as sugar

Because of their low sweetness, manufacturers often blend inulin and FOS with high-intensity sweeteners like stevia, monk fruit, or sucralose.

DIGESTION & METABOLISM

Inulin and FOS provide fewer calories than sugar because they pass through the small intestine undigested. Here's how our bodies process them:

Absorption in the small intestine:
Inulin and FOS are neither broken down nor absorbed in the small intestine.
Fermentation in the large intestine:
Once they reach the large intestine intact, these soluble fibers are fermented by the microbiota (healthy bacteria in the gut), producing gases like methane and carbon dioxide.

This fermentation process has both drawbacks and benefits. On one hand, it can cause digestive issues such as bloating, flatulence, and diarrhea, especially if you’re not used to consuming fiber or consume too much of it. On the other hand, soluble fibers act as prebiotics, by stimulating the growth and activity of gut microbes, and function as fiber by improving bowel function.
How come soluble fiber are not digested and still have calories?
Even though our bodies cannot digest soluble fibers, bacteria in the large intestine can. These microbes ferment the fibers, breaking them down into short-chain fatty acids (SCFAs) and gases. The SCFAs are then absorbed into the bloodstream, providing a small amount of energy—this is why soluble fibers have a low caloric value despite not being digested in the small intestine.

How many calories are in soluble fibers?
Soluble fibers provide fewer calories than sugar, ranging from 1 to 2 calories per gram—less than half of sugar’s 4 cal/g. This translates to about 10 cal per teaspoon, compared to sugar’s 16 cal/tsp.
Inulin ∼ 10 cal/tsp
FOS ∼ 10 cal/tsp

Yacon syrup ∼7 cal/tsp
Yacon powder ∼25 cal/tsp

Are soluble fibers sugar-free?

Yes. While soluble fibers are sugar-free sweeteners, they're not calorie free.

Do soluble fibers affect blood sugar levels?

Soluble fibers are not metabolized into glucose. Having no effect on blood glucose, their glycemic index equals zero:

GI Inulin = 0
GI FOS =0

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FIBERS' CARB COUNT

Counting carbohydrates can be confusing, especially when you realize that not all carbs affect blood sugar the same way. I get a lot of questions about how to count fibers, so here’s what you need to know.

Do soluble fibers count as carbs?

Yes, inulin and FOS are technically carbohydrates and are included in the "total carbohydrates" section of the Nutrition Facts label.

Does inulin and FOS count towards net carbs?

Net carbs refers to carbohydrates your body actually digests and converts into glucose, which raises blood sugar. Since inulin and FOS are not converted into glucose, they do not raise blood sugar, and do not count toward net carbs.

Inulin and FOS – Count as 0 net carbs

Bottom Line:

When calculating net carbs, subtract inulin and FOS completely from the total carbohydrates in the Nutrition Facts label.

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SWEET FIBERS: PROS AND CONS

Advantages of Inulin and FOS:

Sweet taste – Provide sweetness while helping cut back on sugar. They're not very sweet, varying from 10% to 65% as sweet as sugar.
Lower in calories – Offer 50% fewer calories than sugar.
Bulking properties – Add weight and volume to foods, impacting mouthfeel and texture, as regular sugar does.
Enhance browning in baking
Moisture Retention – Keep baked goods moist, extending shelf life.
Digestive health benefits – Act as prebiotic and a fiber.
Non-cariogenic

Disadvantages of Inulin and FOS:

Often associated with adverse digestive issues
Consuming too much soluble fiber can lead to digestive discomfort, including bloating, stomach rumbling, flatulence, cramps, and diarrhea. Individual tolerance varies—some people are more sensitive than others. However, regular consumption can lead to adaptation, meaning that stomach issues may lessen over time.

Soluble tapioca fiber may cause fewer digestion issues than inulin and FOS because it ferments more slowly, resulting in less gas production.

Soluble fiber is a FODMAP carbohydrate, an acronym for Fermentable Oligo-, Di-, Mono-saccharides, and Polyols. The term was coined to designate carbohydrates associated with negative digestive effects.