Shaping Dietary Treatment Expectations and Response in irritable bowel syndrome in participants undergoing a Low Fermentable Oligosaccharide, Disaccharide, Monosaccharide and Polyol Diet.

Three-phase low Fermentable Oligosaccharide, Disaccharide, Monosaccharide, and Polyol Diet (FODMAP) diet: Appointment 1: Phase 1 of the low FODMAP diet (60 minutes). Phase 1 is delivered individually, either in person in the La Trobe telehealth clinic or via a telehealth appointment. Each appointment will be conducted with the same dietitian. Participants will have 60 minutes allocated to the initial appointment with the dietitian. During this time, the dietitian will conduct a thorough initial assessment of the participant in line with the Nutrition Care Process (NCP). Data collection within the NCP will include, but is not limited to, anthropometric measurements (height, weight, waist circumference), biochemical measures (if available from the last six months, such as iron status, blood glucose levels or cholesterol levels), clinical data (bowel habits, energy levels, activity levels) and social data (living arrangements, co-sharing of food shopping and cooking or work status) and dietary assessment (comprehensive diet history). The dietitian will use the supplied template, developed by the study personnel to support data collection of the relevant information pertaining to the participant's anthropometry, biochemistry, clinical signs and symptoms, and dietary assessment. Data collection should take approximately 20-30 minutes of the 60-minute appointment. Following this, the dietitian will provide education on the low FODMAP diet, which will be supplied to the participant. The dietitian will discuss the mechanism by which FODMAPs exert their effect (osmotic and fermentative processes) and note that certain foods are higher in FODMAPs. After education on the mechanisms of action, the dietitian will highlight to participants foods within their current dietary intake that are low, moderate, and high in FODMAPs. The dietitian will discuss additional foods that contain FODMAPs so the participant understands which foods are implicated in exacerbating IBS symptoms. Participants will receive another written resource containing a low-FODMAP meal plan, which the dietitian can further tailor to the participant's food preferences. Additional resources supplied at this time include a low FODMAP shopping guide, an eating out guide and a troubleshooting guide. All resources and materials supplied to the participants have been designed by the trial dietitian specifically for this study. Participants will have the opportunity to ask questions and clarify any food swaps and their wider understanding of Phase 1 of the low FODMAP diet during their consultation. Participants will have four weeks to implement Phase 1, in line with clinical practice guidelines. Appointment 2: Phase 2 of the low FODMAP diet (45 min). Phase 2 is delivered individually, either in person in the La Trobe telehealth clinic or via a telehealth appointment. Participants will return after four weeks for the second appointment with the dietitian. During this appointment, a second NCP will be completed, and used to note changes in anthropometry, biochemistry, clinical signs and symptoms, and dietary intake. Participants will be asked to discuss their symptom response to Phase 1 regarding abdominal pain, changes in bowel movements, and bloating/distention. If the participant feels their treatment response is satisfactory and this is confirmed by the dietitian, who has expertise in IBS symptomatology, the participant will be instructed to initiate Phase 2. The participant will be asked to remain on a low FODMAP diet during Phase 2 to standardise the approach and ensure that FODMAP intake is low enough to determine sensitivity to FODMAP challenges. The dietitian will provide a written resource outlining the types of foods and amounts suitable for challenging each group of FODMAPs. Participants will be shown how to monitor food challenges and symptom responses as each challenge is completed, which will be documented in the written resource provided by the dietitian. This resource was designed by the trial dietitians for this study. FODMAP challenges are known to elicit a symptom response, and increasing the dose of FODMAPs can help determine an individual's tolerance over three days. While some discomfort is expected, it should not be unbearable or disruptive to day-to-day living. Participants will be instructed to discontinue a FODMAP challenge should symptoms increase to the point that they are disruptive to day-to-day living (ability to work, socialise, or complete activities of daily living). At the conclusion of a FODMAP challenge, participants will be instructed to have a three-day washout period to allow any residual gastrointestinal symptoms or FODMAP intake to resolve. The dietitian will work with the participant to identify the most optimal time of the week to undertake challenges, such as weekends or when the participant is in a comfortable environment (such as home, or close to a bathroom) should any unpleasant gastrointestinal symptoms arise. Participants will have eight weeks to complete the FODMAP challenges. It is expected that a minimum of five challenges be attempted in this time. If the participant returns after Phase 1 and reports negligible improvements in symptoms or worsening of any symptom (such as abdominal pain, frequency or consistency of bowel motions, bloating or distention), the dietitian will document this using the NCP. Secondary to documentation, the dietitian will discuss with the participant the risks of continuing (i.e. that is, the participant is unlikely to have any benefit from reintroduction due to already experiencing symptoms and being unlikely to ascertain symptom thresholds with higher FODMAP foods, or potentially worsening symptoms through the introduction of high-FODMAP foods. The dietitian will encourage the participant to cease dietary restriction, and encourage the participant to follow up with their GP or other treating clinicians. Although it would not be appropriate to continue to Phase 2, the participant will be asked if they are willing to complete the 'end of Phase 1’ data collection time point so that the participant's experience can be collected as part of the data set. The participant is at no detriment from declining this request, and their relationship with the study personnel and La Trobe will not be affected. Alternatively, if the participant decides to no longer continue in the study, they have the right to withdraw their data and have it destroyed. The participant should discuss this with the study personnel to ensure their request is met. Appointment 3: Phase 3 of the low FODMAP diet (30 min). Phase 3 is delivered individually, either in person in the La Trobe telehealth clinic or via a telehealth appointment. Following the reintroduction of FODMAPs over an 8-week period, participants will return for their final appointment with the dietitian. Thirty minutes will be allocated to appointment 3, inclusive of completing another NCP, discussing participants' responses to the FODMAP challenges and ensuring they understand their individual tolerance levels. Further written resources will be provided, noting how tolerated foods can be included in the diet, particularly at the threshold at which they were tolerated. If a food did not cause any symptoms, the participant will be instructed to include it without restriction, effective immediately. For any foods whose symptom response was unclear, the participant will be encouraged to re-challenge while remaining on a low FODMAP diet to determine tolerance. Participants will be educated that FODMAP tolerance can change over time and that regular re-challenge of high FODMAP foods is encouraged to liberalise the diet. Participants may complete the 8-week FODMAP reintroduction and feel they have not responded well to this phase. Indicators of poor response may include recurrent and uncomfortable symptoms (pain, altered bowel motions, distention and bloating), and while these may be without reprieve, they should not be worse than when the participant commenced in the study. The dietitian will discuss dietary intake during the previous 8 weeks, including foods that were successfully reintroduced, general adherence to a low FODMAP diet (with the exception of planned challenges), and help to determine if higher-FODMAP containing foods have been consumed, which may have altered the response in Phase 2. Further to this, assessment of participant concerns, readiness and ability to continue will also be discussed between the participant and the dietitian. From this assessment, participants will be given the following options, given that Phase is focused on stabilisation and sustainability, with the goal of liberalising the diet. First, participants can opt to include successfully reintroduced foods, and can continue with a gradual reintroduction at their own pace as this would also reflect maintenance (and re-testing foods in Phase 3 is encouraged). Participants will be encouraged to have a longer washout period before making any further dietary changes, and be encouraged to follow a strict low FODMAP diet for 7 days. Participants will be re-educated on portions sizes (based on an assessment of their dietary intake at this point), ensuring that FODMAP stacking (consuming higher FODMAP-containing foods are not consumed in close proximity) and is not occurring and that dietary fibre intake is adequate/adjusted. Use of acute (one to three days) pharmacotherapy options such as over-the-counter products, hyoscine butyl bromide, simethicone or loperamide for the acute management of abdominal pain or diarrhoea will be permitted, as will the use of gut relaxants and anti-spasmodic agents such as peppermint, gentle exercise or heat packs. Participants will be asked to continue with study data collection points as planned, and to seek immediate contact with the study team if symptoms are troublesome after 14 days (7 days of FODMAP restriction with 7 days of habitual/FODMAP modified eating) for further support if needed. Secondly, if the participant is not able to continue into Phase 3 due to symptoms, cognitive burden, apprehension with trialling foods or other concerns, they will be permitted to conclude the study at this point. The participant will be asked if they are willing to complete the ‘T3 end of Phase 2’ data collection time point so that the participant's experience can be collected as part of the data set. The participant is at no detriment from declining this request, and their relationship with the study personnel and La Trobe will not be affected. Alternatively, if the participant decides to no longer continue in the study, they have the right to withdraw their data and have it destroyed. The participant should discuss this with the study personnel to ensure their request is met. As long-term dietary restriction is not encouraged, the participant will be directed to follow up with their GP or other treating physicians for further support. The study team can provide a letter to the treating professional outlining their response to the study and indicating that alternative management options should be considered. At the completion of each dietitian appointment, the dietitian will complete a checklist that covers the key points discussed (data collection, symptoms and/or bowel function), duration of the appointment (if longer or shorter than the allotted time and why), and deviations the participant has had from the protocol/intervention, any participant questions or actions for follow-up. The dietitian will also complete an assessment of adherence using the following scale: Very adherent b) Fairly adherent c) Partially adherent d) Non-adherent but will try to adhere to diet e) Non-adherent will not adhere to diet Intervention group additional materials and resources: Participants will receive one pre-study consultation, with an allotted duration of 30 minutes, up to one week prior to commencing the trial. Participants will receive a verbal script that the CI, who is a dietitian, will discuss with the participant. The pre-study consultation can be completed face-to-face, by phone call or telehealth. The script will utilise optimistic realism and positive framing to cover the following: 1. A brief introduction to the low FODMAP diet as a management strategy 2. Evidence for the low FODMAP diet 3. Understanding previous unsuccessful attempts of IBS management 4. Expectations for Symptom Response Justification for intervention materials: The additional verbal script, particularly for the intervention group, is designed to enhance expectations while remaining realistic and evidence-based. The low FODMAP diet is well-established in practice and is the most evidence-based dietary intervention for the management of IBS. The statements provided are designed to enhance beliefs about treatment credibility and expectancy, while ensuring that no promises or guaranteed responses are made. The importance of establishing realistic expectations has been established in IBS. It is perceived that the low FODMAP diet will ‘cure’ IBS. Therefore, setting realistic symptom response expectations could improve engagement and satisfaction with the low FODMAP diet (i.e the goal is symptom improvement, not symptom cure). Discussing the likelihood and magnitude of symptom improvement reflects what is observed in the literature. No misleading statements or guaranteed outcomes are promised, and the information is framed with a positive, supportive tone that emphasises autonomy rather than coercion. Moreover, a systematic review on psychological interventions in IBS has stipulated that providing positive yet realistic information can enhance individual expectations. Participants will be clearly informed that responses may vary, and the overall goal is to reduce symptoms rather than ‘cure’ IBS. This will allow us to determine whether there is a benefit to formally integrating discussion around pre-treatment expectations in the counselling methods used to deliver the low FODMAP diet and if this should be further explored in a larger population.