In this special series on Obesity, our host, Dr. Neil Skolnik will discuss the Obesity epidemic with some of the foremost experts in the world.  In Part I we will focus on the epidemiology of obesity, social disparities with regard to obesity, obesity as a chronic disease, the consequences of obesity and some of the reasons that the prevalence of obesity has increased over the last fifty years; in addition we will discuss how to evaluate patients for obesity. This special series is a collaborative project of the American Diabetes Association and the American Academy of Family Physicians and is sponsored by Novo Nordisk and Lilly. Presented by: Neil Skolnik, M.D., Professor of Family and Community Medicine, Sidney Kimmel Medical College, Thomas Jefferson University; Associate Director, Family Medicine Residency Program, Abington Jefferson Health Margot L. Savoy, MD, MPH, FAAFP serves as senior vice president for education, inclusiveness, and physician well-being at the American Academy of Family Physicians Walter C. Willett, M.D., Dr. P.H., Professor of Epidemiology and Nutrition at Harvard T.H. Chan School of Public Health, Professor of Medicine, Harvard Medical School Deborah B. Horn, DO, MPH, Medical Director for the UT Center of Obesity Medicine and Metabolic Performance; Fellowship Program Director, Allison Family Foundation Fellowship in Clinical Obesity Medicine and Metabolism, McGovern Medical School   Selected References: CDC - Adult Obesity Facts @ https://www.cdc.gov/obesity/data/adult.html Sumithran P, Prendergast LA, Delbridge E, eta al. Long-Term Persistence of Hormonal Adaptations to Weight Loss. N Engl J Med 2011; 365:1597-1604 Colditz GA, Willett WC, Rotnitzky A, Manson JE. Weight gain as a risk factor for clinical diabetes mellitus in women. Ann Intern Med. 1995; 122:4816. Koh-Banerjee P, Wang Y, Hu FB, Spiegelman D, Willett WC, Rimm EB. Changes in body weight and body fat distribution as risk factors for clinical diabetes in US men.Am J Epidemiol. 2004; 159:11509.