[Functional Constipation].

Functional constipation (FC), also referred to as chronic idiopathic constipation, is defined by infrequent bowel movements, hard stools, straining, a sense of incomplete evacuation or anorectal blockage, and the need for digital maneuvers in the absence of structural or biochemical abnormalities. According to the Rome IV criteria, FC is diagnosed when these symptoms have persisted for the previous three months, with onset occurring at least six months before diagnosis. FC can be classified into three subtypes based on the colonic transit and defecatory function: normal transit constipation, defecatory disorders, and slow transit constipation, with overlapping or mixed forms frequently observed in clinical practice. Nevertheless, the roles of dietary and lifestyle factors in the development and persistence of FC are incompletely understood. Against this background, the Diet, Obesity, and Metabolism Research Study Group of the Korean Society of Neurogastroenterology and Motility developed visual materials outlining dietary and lifestyle factors relevant to functional gastrointestinal disorders to provide practical guidance for clinicians and patients. This review introduces the FC section of these materials and provides a comprehensive summary of their contents.