Added fibres: why a high-fibre bar can wreck your afternoon

Added fibre is the only additive class sold as a benefit. Manufacturers put inulin and chicory root fibre into bars, yoghurts and cereals so the label can claim a high fibre content, and for most people that is a genuine improvement.

For anyone with a sensitive gut, added fibre is also the most common reason a "healthy" product causes trouble.

Inulin, chicory root fibre and the other added fibres

Four ingredients account for most of the fibre added to food.

Inulin is a fructan, extracted from chicory root or Jerusalem artichoke. Chicory root fibre is the same thing under a different name, and labels use both.

Polydextrose is manufactured from glucose. Soluble corn fibre comes from corn starch.

All four are soluble, fermentable fibres. None of them are digested in your small intestine. All of them arrive in your colon intact, where bacteria ferment them. Feeding those bacteria is the reason manufacturers add them.

Why added fibre causes bloating

Fermentation makes gas. In a gut that tolerates distension well, that is unremarkable. In a gut that does not, it is bloating, cramping and wind.

Inulin is a fructan, so it is a FODMAP, and a high-FODMAP one. A protein bar with eight grams of inulin delivers more fructan than a serving of onion, in a product bought because it seemed like a healthy choice. We cover the mechanism in high-fructan foods.

Inulin can be good for most people and still cause you trouble, because the high fibre claim on the label is about the average person.

The full list

This table lists every added fibre in our database.

Food	Notes
PolydextroseE1200	Polydextrose (E1200) is a fibre food additive.
Soluble corn fiber	Soluble corn fiber is a fibre food additive.
Inulin	Inulin is a fibre food additive.
Chicory root fiber	Chicory root fiber is a fibre food additive.

Where they turn up

Protein bars and meal-replacement bars are the worst offenders, because inulin adds fibre and sweetness at once.

Also: high-fibre yoghurts, "gut health" drinks, low-sugar chocolate, keto and low-carb baked goods where inulin replaces flour, some breakfast cereals, and most fibre supplements sold as prebiotics.

Anything marketed on gut health is worth turning over.

What to do about it

If you tolerate fibre well, these are fine and probably good for you. The prebiotic effect is real and the research behind it is reasonable.

If you have IBS or react to FODMAPs, added fibres are worth treating as a suspect before more obvious foods. They deliver a concentrated dose in a small portion, which is unusual, and they appear in products nobody thinks to blame.

If you want the prebiotic benefit anyway, dose matters. Tolerance to inulin builds with gradual exposure for many people, so a small amount daily is easier to handle than eight grams in one bar. Partially hydrolysed guar gum is often the easiest of these to tolerate. The trial usually cited for it studied children, so treat it as a lead.¹

How to test it

Cut products carrying added fibre for two weeks: check bars, yoghurts, low-sugar chocolate and any supplement sold as a prebiotic.

Then reintroduce one product, at a normal serving, and see what happens over the next day. If a protein bar causes what a bowl of oats does not, you have found something specific and useful.

Journal your day in 30 seconds, find your triggers.

Where Triggerbites fits in

You type or say your day the way you'd tell a friend: "a high-fibre yoghurt and a coffee for breakfast, a protein bar at 11, soup and a roll for lunch, bloated and crampy all afternoon". Name the brand of the bar and Triggerbites finds the product in a catalog of over a million, with the inulin or chicory root fibre listed as an ingredient. You can also scan the barcode or photograph the label.

Inulin is the ingredient people least expect to cause symptoms, because it arrived in something they bought to be healthier. The app counts it with everything else you ate, so when a pattern shows up across a few weeks it can point at the bar. You can take the record to your dietitian as a PDF.

Log your day in 30 seconds

Text, voice or photo. Log as you go, or recap it all in the evening.

Your food, broken down

Meals become ingredients and sensitivity profiles: histamine, salicylates, FODMAPs, allergens, and even the additives on packaged food.

Everything in the same journal

Symptoms, supplements, sleep, stress, exercise and mood, beside what you ate.

See what repeats over time

Patterns between what you eat and how you feel, including delayed reactions that show up days later.

Triggerbites Features

• Log your day in 30 seconds: Text, voice or photo. Log as you go, or recap it all in the evening.
• Your food, broken down: Meals become ingredients and sensitivity profiles: histamine, salicylates, FODMAPs, allergens, and even the additives on packaged food.
• Everything in the same journal: Symptoms, supplements, sleep, stress, exercise and mood, beside what you ate.
• See what repeats over time: Patterns between what you eat and how you feel, including delayed reactions that show up days later.

Common questions

What is inulin?

A fructan extracted from chicory root or Jerusalem artichoke, added to food so the label can claim high fibre. Chicory root fibre is the same thing under a different name. It is not digested in your small intestine and is fermented in your colon.

Why does a high-fibre bar make me bloated?

Because fermentation makes gas. Inulin is a high-FODMAP fructan, and a bar with eight grams delivers more fructan than a serving of onion. In a gut that tolerates distension poorly, that is bloating and cramping.

Is inulin bad for you?

For most people, the opposite. Feeding gut bacteria is why it is added and the prebiotic effect is real. It causes trouble specifically in people who react badly to the gas that fermentation produces.

Which products contain added fibre?

Protein and meal-replacement bars are the worst, because inulin adds fibre and sweetness at once. Also high-fibre yoghurts, gut health drinks, low-sugar chocolate, keto baked goods and most prebiotic supplements.

Can I build tolerance to inulin?

Many people can, with gradual exposure. A small amount daily is easier to handle than eight grams in one sitting. Partially hydrolysed guar gum is often the easiest fibre to tolerate, though the trial most often cited for it studied children.

How do I test whether added fibres affect me?

Cut products carrying them for two weeks, checking bars, yoghurts, low-sugar chocolate and any prebiotic supplement. Then reintroduce one product at a normal serving. If a protein bar causes what a bowl of oats does not, you have your answer.

Live, love, log. 🧡