The Obesity workgroup reviews the research literature on screen media exposure and obesity and physical activity and eating behaviors, and makes recommendations for future research and public policy. Obesity is one of the best documented outcomes of screen media exposure. Evidence exists both from observational studies demonstrating associations between screen media exposure and increased risks of obesity, and randomized controlled trials of reducing screen demonstrating cause-and-effect relationships with reduced weight gain in children. Evidence supports increased eating while viewing, exposure to high-calorie, low-nutrient food and beverage marketing, and reduced sleep duration as the most significant mechanisms linking screen time and obesity. Interactive media may also hold promise for improving eating and physical activity behaviors to prevent or reduce obesity. Future interdisciplinary research is needed, particularly experimental research examining the effects of newer mobile and other digital media exposures on obesity.