Using cell phones to deliver a weight control intervention in this age group has the potential to be engaging, enjoyable, practical, cost-effective, sustainable, and broadly disseminated. We propose a trial in which a highly innovative but more risky intervention based almost entirely on use of cell phone technology and a second more incremental innovation over traditional behavioral intervention are each compared to a usual care control group. We will recruit a diverse target population of overweight/obese, generally healthy young adults, comprising approximately 35% non-Latino Whites, 35% non-Latino Blacks, and 30% Latinos, to be randomized to: 1) Usual care control: Educational materials and information but no behavioral intervention; 2) Cell-phone intervention: similar education and knowledge as the control group, but thereafter a behavioral intervention will be delivered almost exclusively via cell phone, particularly using the self-monitoring and social networking features of this technology; 3) Personal contact with cell-phone enhancement: personal contact intervention enhanced by cell-phone for self-monitoring.