The American Society for Metabolic and Bariatric Surgery defines obesity as a disease in which fat has accumulated to the extent that health is impaired leading to increased health problems and reduced life expectancy. Obesity is considered a multifactorial disease with a strong genetic component. Acting upon a genetic background are a number of hormonal, metabolic, psychological, cultural and behavioral factors that promote fat accumulation and weight gain. The global method of calculating your obesity is BODY MASS INDEX.