The complexity of the obesity epidemic requires the cooperation of key stakeholders in this effort. No one sector, academia, government, industry, or health care, has been successful in combating this disease to date. On March 10-11, 2004, The Harvard Medical School Division of Nutrition hosted the symposium "Science-Based Solutions to Obesity: What is the Role of Academia, Government, Industry, and Health care?" as a platform to address the role of these stakeholders, both individually and collectively, in combating the nation's epidemic of obesity. The proceedings from the symposium, included in this supplement, discuss the following: the science of obesity-related topics such as genetics, protein and weight loss, portion size, energy density, and behavior; the need for more aggressive government policies; industry's role in using research and development capabilities to promote healthier, portion-controlled products; and how to translate nutrition information from medical doctors to patients.