Obesity is a worldwide problem with increasing prevalence and incidence in both developed and developing countries. In older adults, excess weight is associated with a higher prevalence of cardiovascular disease, metabolic disease, several important cancers, and numerous other medical conditions. Obesity has been also associated with increased functional limitations, disability, and poorer quality of life. Additionally, obesity has been independently associated with all-cause mortality. The obesity epidemic has important social and economic implications, representing an important source of increased public health care costs. The aim of this review is to report the epidemiology of obesity world-wide and the implications of obesity on disability and chronic diseases.