Six years ago, when JAMA last published a theme issue on obesity, there was optimism that progress was being made in preventing and treating obesity.1 As time has passed, so too has the optimism, as reports continued to show that the prevalence of obesity was increasing2 and, most important, rapidly increasing in children.3 A year and a half ago, there was a call to reconsider obesity and view it in new ways with the hope of better managing this very consequential clinical problem.4 In response, JAMA has revisited obesity in the form of a theme issue.