 The majority of adult Americans consume a high saturated fat diet, have a low fruit and vegetable FV intake, and lead a sedentary lifestyle. This unhealthy lifestyle heightens their risk for cardiovascular disease and cancer. Improving diet and activity can reduce risk, but the best prescription to promote a healthier diet and a more active lifestyle remains unknown. This study will randomly assign participants to 4 groups, which will include all combinations of increasing healthy eating and activity and decreasing unhealthy eating and activity. The Familiarity Hypothesis predicts that the most familiar dieting prescription decrease fat, increase physical activity will maximize healthy behavior change. The Optimal Substitution Hypothesis, based on Behavioral Economic Theory, predicts that increasing FV intake while decreasing sedentary behavior will surpass alternative methods by maximizing behavioral substitution of healthful eating and activity for unhealthful eating and activity. The Low Inhibitory Demand Hypothesis, based on Self-Control Theory, predicts that increasing FVs while increasing physical activity will be most successful because this prescription places the fewest demands on self-control resources. 