Diabetes mellitus is defined as a group of chronic disorders involving the metabolism of carbohydrates, fats, and proteins, characterized by the fundamental feature of hyperglycaemia, resulting from an absolute or relative deficiency of the hormone insulin. Diabetes mellitus can be classified into four major groups: type 1 diabetes, type 2 diabetes, gestational diabetes, and other specific types of diabetes that arise as a consequence of other pathological processes. Common comorbidities associated with diabetes, among others, include eating disorders, such as bulimia nervosa. Bulimia nervosa is a disorder characterized by recurrent episodes of overeating. The disorder shares similarities with binge eating disorder (BED), but it differs in the fact that bulimia nervosa episodes of overeating are followed by behaviours such as vomiting, laxative use, emetic use, or diuretic use. The bulimic eating pattern has been shown to adversely affect glycaemic control. It is also worth noting that individuals with disordered eating patterns who have diabetes are at three times greater risk of developing diabetic retinopathy.The development of complications is also influenced by the presence of a disorder known as diabulimia, which refers to the practice of skipping or using smaller doses of insulin as a method of purging, leading to even more pronounced inadequate glycemic control. Understanding the association between bulimia nervosa and the onset and progression of diabetes is of utmost importance in planning therapy, which, in addition to pharmacological regulation of plasma glucose, must involve monitoring patients' eating patterns and, if necessary, providing psychiatric assistance.