This randomized controlled trial will examine the effects of a PA prescription of TV commercial stepping for at least 90 min/day of TV programming, with that of walking at least 30 min/day (30 min walk) on daily step counts, TV viewing, and diet during a 24 week PA intervention. Sedentary, overweight or obese, adults will be randomly assigned to either the TV commercial stepping, or 30 min walk group during a 24-week behavioral PA intervention. Both groups will attend 8 sessions, but receive different PA goals. PA, TV watching time, diet, and anthropometric data will be collected at 0, 12, and 24 weeks. It is hypothesized that the TV commercial stepping condition will, show an equal increase in PA at 12 and 24 weeks as compared to the 30-min walk condition. Neither group is hypothesized to demonstrate changes in TV viewing time, dietary intake, or weight.