Weight gain accelerates during early adulthood, and leads to the health consequences of obesity (high blood pressure, diabetes, heart disease, etc). Most weight loss studies enroll middle-aged adults. This study tests the hypothesis that a weight loss intervention that builds on prior research evidence but is enhanced with technological innovations will lead to weight loss in a diverse group of overweight and obese adults aged 18-35 years. The technology intervention, using cell phone applications, will be compared to an "advice only" control group and to a group receiving a more traditional personal coaching intervention.