BACKGROUND: The low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet is an effective dietitian-led treatment for irritable bowel syndrome (IBS). An increasing demand of IBS patient referrals has warranted group FODMAP education led by specialist dietitians. Psychological co-morbidities are common in IBS, although how the low FODMAP diet influences psychological outcomes is not understood. The present study aimed to evaluate symptom related outcomes of the diet following group education and assess its effect on psychological profiles. METHODS: An observational, prospective study was conducted in 55 IBS patients who attended FODMAP Restriction and FODMAP Reintroduction group sessions. Data were collected at baseline and follow-up after FODMAP Restriction and analysed using descriptive and McNemar's tests. Primary outcome was evaluated by IBS Symptom Severity Score (IBS-SSS). Secondary psychological outcomes included anxiety and depression using the Hospital Anxiety and Depression Scale (HADS) and risk of eating disorder questionnaire (SCOFF). RESULTS: After FODMAP Restriction, 27 of 55 (54%) patients reported clinically relevant symptom improvement, as defined by a reduction in the IBS-SSS ≥50 points, whereas no differences were recorded in the proportion of patients identified with clinical anxiety (p = 1.000) or clinical depression (p = 0.375). Positively, no increased risk of an eating disorder was observed. CONCLUSIONS: The present study provides data supporting the efficacy of the low FODMAP diet in IBS patients who attended dietitian led group education settings in tertiary care. Clinically significant improvements in gastrointestinal symptoms were observed, although with no impact on clinical levels of anxiety, depression or the risk of an eating disorder.