Short-Term Effects of Low-FODMAP, NICE Dietary Advice, and Intermittent Fasting in Irritable Bowel Syndrome

The goal of this clinical trial is to compare the short-term effects of three dietary approaches in adults with irritable bowel syndrome (IBS): a low-FODMAP diet, adapted National Institute for Health and Care Excellence (NICE) dietary advice, and adapted NICE dietary advice combined with 16:8 intermittent fasting. The main questions this study aims to answer are: How do these three dietary approaches affect IBS symptom severity after two weeks? How do these three dietary approaches affect IBS-related quality of life after two weeks? The researchers hypothesize that the low-FODMAP diet will produce the greatest short-term reduction in IBS symptom severity. The study will also explore whether adding 16:8 intermittent fasting to adapted NICE dietary advice provides additional benefit. Researchers will compare the three dietary groups to determine whether the changes in IBS symptoms and quality of life differ between the dietary approaches. Participants will: Follow one of the three dietary approaches for two weeks. Attend study visits at the beginning of the study, after one week, and after two weeks. Keep records of their food and fluid intake. Complete questionnaires about IBS symptoms, quality of life, anxiety, and depression. Record their stool form and frequency during the study.