Why fibre makes you bloated (and how to avoid it)

Yes, fibre can bloat you — here's why

When fermentable fibre reaches your colon, bacteria break it down and release gas as a by-product. Add a lot of fast-fermenting fibre at once and that gas arrives in a spike — the bloating and flatulence people notice by mid-afternoon. A meta-analysis found flatulence was higher in fibre groups than controls (van der Schoot et al., AJCN, 2022), and inulin-tolerance trials show the effect rises with dose (Bonnema et al., 2010).

It's a common reason people give up

This isn't a willpower problem. In a large fibre trial, 36–44% of people had stopped within three months — including the placebo arm, which shows how hard any daily habit is to keep (Bijkerk et al., BMJ, 2009).

How to add fibre without the bloat

Start low and build up. If you currently eat little fibre, begin with half a normal dose for a week and increase slowly so your microbiome adapts.

Drink water. Viscous fibres like psyllium absorb water to form a gel, so adequate fluid intake matters.

Pace fast and slow fibres together. Fast-fermenting fibres taken alone spike gas; slower, viscous fibres spread fermentation out. In one RCT, psyllium taken with inulin produced less breath hydrogen (gas) than inulin alone (Gunn et al., Gut, 2022) — a published example of how combining fibres can change gas patterns.

When bloating is something else

Persistent bloating unrelated to fibre changes, or bloating with pain, weight loss or altered bowels, deserves a clinician's review. And if you're on a clinician-directed low-FODMAP plan, note that inulin is a FODMAP — check before adding it.

Buta-8 combines fermentable fibres with viscous psyllium; individual responses to fibre vary, so introduce it gradually. See the ingredients →

References: van der Schoot et al., AJCN 2022; Bonnema et al. 2010; Bijkerk et al., BMJ 2009; Gunn et al., Gut 2022.