Sleep loss, circadian disruption, and sleep disorders affect mortality, morbidity, safety, performance, and mood.1 Although sleep is essential for humans, there is a persistent societal misconception that sleeping too much means gaining weight because less energy is exerted when sleeping. Historically, individuals who slept a lot were often portrayed as being overweight and lazy, and in the modern work- and activity-obsessed culture, getting less sleep can be viewed as a badge of honor. The randomized clinical trial by Tasali et al2 in this issue of JAMA Internal Medicine corrects the misconception that more sleep leads to weight gain and, in the process, enhances our understanding of how sleep affects energy intake and weight loss. The findings of this trial are especially important given the high community prevalence of obesity.