Obesity is a global epidemic and its prevalence continues to increase in many developed and developing countries. This brief review provides an update on the prevalence of obesity in the USA and globally, reviews the underlying mechanism of several comorbidities associated with obesity, and discusses the economic burden of obesity. Although the overall prevalence of obesity in the USA is not increasing, racial and ethnic minorities continue to struggle with rising obesity rates. Globally, the largest increases are being observed in the developing countries. Given the comorbidities associated with obesity and its immense economic burden, nearly every country will soon struggle with the financial and healthcare implications of the epidemic.