Does fiber supplement break a fast?

Q: Does fiber supplement break a fast?

Maybe - use caution. Depends on fiber type and sweeteners. Fiber can trigger digestion and fullness even when calories are modest. Use unsweetened fiber with plenty of water, or move it to the eating window if your stomach reacts.

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Use caution

Depends on fiber type and sweeteners

5-45 kcal

Maybe - use cautionmedium confidenceSupplement-label evidence

Decision

Maybe - use caution. Some fiber supplements are low calorie; others include sugar, flavoring, or carbs.

Reason

Fiber can trigger digestion and fullness even when calories are modest.

Evidence

Supplement facts panels vary widely for fiber powders and ready-to-drink mixes.

How we calculate this value

Base tier: 60/100 for "Use caution". Item adjustment: -5 points for calories, nutrient signal, product variability, and safety caution. Final Fast Score: 55/100.

What to do

Use unsweetened fiber with plenty of water, or move it to the eating window if your stomach reacts.

Medical caution

Separate fiber from medications if your clinician or label warns about absorption timing.

References for this answer

Methodology

NIH Office of Dietary Supplements: Dietary Supplements for Exercise and Athletic Performance NIH Office of Dietary Supplements: Dietary Supplement Fact Sheets U.S. Food and Drug Administration: Dietary Supplements MedlinePlus, National Library of Medicine: Taking multiple medicines safely