The purpose of this study is to examine the psychological benefits of chronic exercise as well as the effects of exercise training on eating behaviors and stress-induced overeating in overweight and obese women. Participants will be randomized to an 12-week exercise condition or a delayed exercise condition. Assessments will occur at baseline, 6 weeks, and 12 weeks and will include answering surveys in real-time using smartphones, several assessments of eating behaviors and dietary intake, and questionnaire measures of factors which could mediate the relationship between exercise and eating. Participants will be compensated for completing assessments and for adherence to the exercise protocol.