Although research shows family members can influence each other's diet and exercise behaviors, the specific strategies that most effectively motivate individuals to enact healthy behaviors have not been revealed. Toward this goal, this study employed confirmation theory to assess how the quality of weight management (WM) communication between 107 mother-teen dyads was related to their diet and exercise behaviors as well as their subjective perceptions of the productivity of WM conversations. Confirmation theory proposes two components of confirmation: acceptance and challenge. Analyses revealed that accepting and challenging communication were both positively related to the perceived productivity of WM conversations. However, more complex associations emerged for diet and exercise. Acceptance was more helpful in motivating better eating habits for mothers with low health motivation and teens with high health motivation. For exercise, challenge was helpful in motivating teens with higher sensitivity about communicating about weight issues; however, counter to predictions, challenge was negatively related to exercise for teens with low health motivation and low sensitivity. These interactions, however, explained less variance than analyses for perceived effectiveness and satisfaction.