The low FODMAP diet now has good evidence for use in the treatment of patients with irritable bowel syndrome (IBS). The use of the diet in practice is not a one-size-fits all approach. Importantly, patients are encouraged not to remain on a strict low FODMAP diet in the long term.
The re-challenge phase is crucial to assist patients to identify specific dietary triggers, improve prebiotic intake and reduce the level of dietary restriction required. Limited evidence is available to guide best practice. However, in practice, beneficial outcomes can be seen through strategic food challenges.
Dietitians should tailor the challenge process to the individual patient and their needs. Food challenges should aim to improve dietary variety, ensure nutritional adequacy and be in line with patient preferences. Identifying FODMAP subgroups most likely to trigger symptoms is a helpful tool. This can assist the patient to re-introduce moderate-high FODMAP foods back into the diet that are less likely to cause symptoms. Dosage and frequency of intake can also be taken into consideration. The outcome of the re-challenge process aims to find a balance between good symptom control and expansion of the diet.
Additional challenges that face dietitians include those with multiple dietary restrictions such as vegetarians or patients with diabetes who are simultaneously following a low FODMAP diet. Ensuring nutritional adequacy in these patients is essential. Strategies to reduce the restrictiveness of the low FODMAP diet would be of benefit. Such strategies may include reducing the FODMAP content of foods through changes to cooking methods. Other strategies include ways to improve the absorption of FODMAPs, such as the addition of glucose to fructose. However, data to support the symptomatic improvement from these strategies are limited.