## 1 Introduction  
Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder characterized by recurrent abdominal pain, bloating, abdominal discomfort, and changes in bowel habits without any underlying conditions [1]. In recent years, the prevalence of IBS has been increasing in Asia [2]. It is reported to be particularly common in young adults aged <45 years, and women are reported to develop IBS at a higher rate than men [3]. The main factors associated with IBS symptoms include altered intestinal motility and sensitivity, brain-gut axis dysregulation, stress, socio-psychological and genetic factors, gut microbiota changes, lifestyle, and dietary factors [1, 4, 5]. Among these, dietary factors can help alleviate symptoms depending on an individual's level of knowledge and efforts to improve dietary habits [4, 6], and eating a balanced diet is the most critical factor in improving symptoms because it has fewer side effects than medications [7]. However, as each person with IBS has a different set of triggers [6, 8], successful dietary therapy will likely require identifying and monitoring these triggers.  
Multiple sessions with a registered dietitian can be effective, particularly for multifactorial conditions such as IBS [8]. However, under normal circumstances, consultation with a dietitian requires a visit to a medical center that can be inaccessible and expensive [9, 10, 11].  
In addition, the number of patients with IBS is increasing. Still, the number of dietitians is limited, which limits the ability of dietitians to provide continued nutritional management and appropriate feedback to a large number of patients with various symptoms of IBS [7]. Therefore, it is necessary to explore nutritional interventions that can manage the eating habits of patients with IBS without being limited by staffing, cost, or location.  
Recent advances in information technology have led to an increase in the use of mobile devices, and mobile health has been recognized as an effective platform for health promotion [12; 13]. Mobile-centric technology effectively provides easy access to healthcare information and helps participants with chronic diseases learn about their illnesses and self-management [14; 15]. Research has shown that self-management tools, such as mobile health services, are effective in assisting individuals to improve their eating habits and make lifestyle changes [16]. Self-management, including dietary and lifestyle changes, is more effective than medication in improving symptoms in the long run [7]. Mobile health services are likely helpful in managing IBS symptoms because they are easily accessible without time, cost, personnel, and location limitations.  
Information-Motivation-Behavioral Skills (IMB), a theory on behavioral changes related to health, states that individuals acquire information and are motivated to change their behavior. Improving health behavior skills leads to increased behavioral change and self-efficacy [17]. This model has been used as a theoretical framework for developing intervention programs for health behavioral changes in various chronic diseases, including diabetes, osteoarthritis, obesity, human immunodeficiency virus infection, heart disease, and gout [18; 19; 20; 21; 22]. Therefore, web-based nutrition education based on the IMB model is considered appropriate for maintaining and promoting behavior changes in patients with IBS by providing information, motivation, and behavioral skills that can be consistently implemented daily.  
This study aims to evaluate the effectiveness of developing and applying a mobile health self-management program based on the IMB model for managing symptoms in patients with IBS.