Institute of Performance Nutrition

The low-FODMAP diet has solid evidence behind it. Indefinite strict elimination without reintroduction does not.

The protocol has three phases: elimination, reintroduction, and personalisation. The elimination phase is designed to last 2–6 weeks. The goal is the least restrictive diet that manages symptoms — not the strictest one possible.

When elite marathon runners self-prescribe from general IBS blogs and never progress to reintroduction, the impact can be a problem: displaced carbohydrate intake, declining iron and calcium, reduced gut microbiome diversity, and an inability to practise race-day fuelling — 8 weeks before the most important race of their season.

This week's IOPN newsletter breaks it all down through a detailed elite athlete case study.

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