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IBS

IBS: why gut symptoms follow meals, infections and days the way they do

Irritable bowel syndrome is a disorder of gut-brain interaction with measurable physiology: heightened sensitivity, altered motility, and a nervous system that responds to meals within seconds. These explainers cover the timing puzzles people live with.

Explainers

Pattern stories about ibs

IBS

Why IBS hits minutes after a meal, when the food is still in your stomach

Solid food takes 2 to 5 hours to reach the colon, so cramps five minutes into a meal cannot be 'the food going straight through'.

Read the explainer IBS

Why a stomach bug can leave a years-long footprint in the gut

About 1 in 7 adults meet IBS criteria months after infectious gastroenteritis, with 4.3 times the odds of unexposed people.

Read the explainer IBS

Why the same food can hurt on Tuesday and not on Friday

84% of people with IBS report food triggers, yet 61% of their real-life meals cause no symptoms, and up to a third of people flare on blinded placebo.

Read the explainer Tracking

What a symptom log can tell you, and what it cannot

Memory inflates past symptoms, exposures happen together, and flares change your sleep and stress rather than the reverse.

Read the explainer

What the evidence supports, in one place

  • Pain minutes after eating is the gastrocolonic reflex acting on an oversensitive gut, moving contents that were already in the lower bowel. Solid food takes 2 to 5 hours to reach the colon.
  • Food triggers are inconsistent because a meal is a combination: 61.4% of real-life meals logged by people with IBS caused no symptoms, and 26 to 35% of people flared on blinded placebo. Dose, fat, fermentation carryover over 1 to 3 days, and expectation all move the response.
  • After a stomach bug, about 1 in 7 adults meet IBS criteria months later. Roughly 85% recover without lasting symptoms, and around 60% of those with post-infectious IBS no longer meet criteria five years on.
  • Tracking corrects memory and shows what moves together. It cannot prove a trigger; eight experts reading the same food diaries agreed on almost nothing.

Red flags that need a clinician

Rectal bleeding or black stools, unexplained weight loss, symptoms that wake you from sleep, unexplained anaemia, persistent fever, new symptoms after age 50, or a family history of bowel cancer, inflammatory bowel disease or coeliac disease. These are not typical of IBS.

Every figure above is sourced and discussed in the linked explainers. This page summarises; it does not add claims.

Written by Laxmanna · Research-led health writer. Every explainer on Unflame starts from a structured evidence dossier: primary studies retrieved, claims tabulated, contradictions logged, and wording checked against what the sources can support. How the dossiers are built.