The low fermentable, oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet has good evidence for use in the treatment of patients with irritable bowel syndrome. Importantly, patients are encouraged not to remain on a strict low FODMAP diet long-term, and many patients maintain symptom improvement with a relaxed, moderate FODMAP restriction. The re-challenge phase is crucial to assist patients in identifying specific dietary triggers, reduce the level of dietary restriction required, and increase prebiotic intake. Limited evidence is available to guide best practice, but, in practice, beneficial outcomes can be seen through strategic food reintroductions. Here, we set out some practical recommendations based on clinical experience. Dietitians should tailor the challenge process to the individual patient and their needs. Food challenges should aim to improve dietary variety and nutritional adequacy while considering specific food preferences and usual dietary habits. Identifying FODMAP subgroups that are well tolerated is helpful, allowing the reintroduction of some moderate to high FODMAP foods back into the diet without symptom induction. FODMAP subtypes that are less well tolerated may also be reintroduced, but dosage and frequency of consumption need to be individualized. Additional challenges that face dietitians include consideration of patients with multiple dietary restrictions such as in vegetarians or patients with diabetes who are simultaneously following a low FODMAP diet. Ensuring nutritional adequacy is essential. The outcome of the re-challenge process aims to find a balance between good symptom control and expansion of the diet.