**2. Defining obesity as a chronic illness**

Obesity is recognized as a complex, chronic and progressive disease by the World Health Organization (WHO) as well as multiple international medical and scientific

societies, requiring lifelong treatment, monitoring, and control [3]. The CDC defines chronic disease as conditions lasting greater than one year that require ongoing medical attention or limit activities of daily living, or both. Obesity is associated with three of leading chronic diseases - heart disease, cancer, and type 2 diabetes. There are widespread consequences of obesity compared to normal or healthy weight for many serious health conditions, including all causes of death, hypertension, diabetes mellitus, coronary heart disease, stroke, and many cancers. Chronic diseases need to be treated and monitored for an individual's lifetime. While patients' chronic diseases may improve with management, relapse can and does happen.

Obesity affects not only individual physiology but also individual psychology. Pre-existing psychological conditions, as well as post-operative conditions that can be created or exacerbated after bariatric surgery, need to be understood, treated, and followed. Recognizing the interaction and impact of obesity on psychopathology, as well as how to identify and treat related psychological disorders, continues to be a work in progress for the obesity medicine field.
