Eating disorders are complex diseases with multifactorial causes. According to the Diagnostic and Statistical Manual of Mental Disorders text version (DSM-5-TR) and the WHO International Classification of Diseases and Related Health Problems (ICD-11), the major types of eating disorders include anorexia nervosa, bulimia nervosa, and binge eating disorder. The prevalence of eating disorders is alarmingly increasing globally. Moreover, the COVID-19 pandemic has led to more development and worsening of eating disorders. Patients with eating disorders exhibit high rates of psychiatric comorbidities and medical comorbidities such as obesity, diabetes, and metabolic syndrome. This paper aims to review and discuss the comorbidities of eating disorders with those metabolic diseases. Eating disorder treatment typically includes a combination of some or all approaches such as psychotherapy, nutrition education, and medications. Early detection and intervention are important for the treatment of eating disorders.