On October 31, 2001, Grantmakers In Health (GIH) convened an Issue Dialogue in Washington, DC, on the problem of obesity and its implications for personal and public health. The purpose of this meeting was to help the staff and trustees of health foundations and corporate giving programs understand the nature of today's epidemic and explore ways in which they could play a role in identifying and promoting effective solutions. In addition to discussing the scope and implications of overweight and obesity in the United States, presenters and discussants provided insights into the strategies that grantmakers might want to consider to address this serious health problem. This Issue Brief incorporates the information and ideas shared during the meeting into the background paper which was prepared for participants at the Issue Dialogue. It offers detailed data on the prevalence and growth of overweight and obesity in various populations, discusses their impact on health and the costs of care, reviews the major causes, and suggests strategies for both prevention and treatment. In the context of those strategies, this report also profiles a number of efforts by both grantmakers and government agencies to tackle some of the root causes of this important public health issue.