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FODMAP and IBS

A sensitivity, not an allergy. Nothing is being damaged — but the discomfort is real, and the diet that helps is a three-step process people very often stop halfway through.

What FODMAPs are

Short-chain carbohydrates that many people absorb poorly: Fermentable Oligosaccharides (fructans and GOS), Disaccharides (lactose), Monosaccharides (excess fructose) and Polyols (sorbitol and mannitol).

They draw water into the bowel and are fermented by gut bacteria, producing gas. In most people that is entirely normal and unnoticed. In irritable bowel syndrome the gut is more sensitive to the resulting stretch, so the same ordinary process causes bloating, pain, wind and changes in bowel habit.

The mistake almost everyone makes

The low-FODMAP diet is one of the better-evidenced approaches to IBS. It is also frequently done wrong, in one specific way: people cut everything out, feel better, and stay there.

The restricted phase is a diagnostic tool, not a destination. Staying on it long-term narrows your nutrition and reduces the diversity of your gut bacteria — which is not a neutral trade. The point of the protocol is to find your own thresholds and then eat as broadly as you possibly can.

The three steps

Elimination, 2 to 6 weeks. Cut high-FODMAP foods and see whether symptoms actually settle. If nothing improves, FODMAPs may not be your driver — genuinely useful to learn early rather than after months.
Reintroduction, one group at a time. Challenge each of the six groups over about three days, increasing the amount, then leave washout days before the next. One at a time is the whole point: test two together and a reaction tells you nothing about which caused it.
Personalisation. Restrict only what you actually reacted to. Everything you tolerated goes back on the menu.

Doing this with a dietitian is genuinely better if you can. They catch the mistakes that make results meaningless — reintroducing too fast, testing two groups at once, or attributing a bad week to a food when it was really a bad month.

Food is not the only lever

Regular meals, sleep, stress and gentle activity all move IBS symptoms independently of what you eat. It is easy to blame a food for a week that had other things going on in it.

What Biomon does

It tracks the protocol — the part usually done on paper and abandoned around week three. It counts your elimination days against the minimum and flags when you have run past the point the phase is meant to last. It schedules challenges one group at a time with washouts between, and records what you decide happened.

It never decides tolerance for you. That is a judgement about your own body, ideally made with a dietitian, and these answers shape what you eat for years. An app inferring "you reacted to lactose" from a symptom log would be claiming an authority it does not have.

Biomon's food classifications are general published guidance, not laboratory measurements, and carry no gram values. Serving size matters enormously in this diet — Monash University's own app has tested per-serving values if you need that precision.

When to see a doctor

IBS is diagnosed by ruling other conditions out, so get symptoms assessed before treating them with a restrictive diet. See a doctor promptly for blood in your stool, unintended weight loss, difficulty swallowing, fever, symptoms that wake you at night, anaemia, a family history of bowel cancer, coeliac disease or inflammatory bowel disease, or new bowel symptoms starting over the age of 50. Those need investigation, not a diet.

Gout →

The other condition where food is a real, trackable lever.

Sleep debt →

Sleep moves IBS symptoms independently of what you eat.

This is general wellness information, not medical advice. Biomon is not a medical device and nothing here is a diagnosis. If something about your health concerns you, talk to a doctor.