Background: Dairy consumption amongst North Americans aged 30–50 has been declining. Targeted messages have been identified as a cost-efficient method through which to increase health-enhancing behavior, such as dairy intake.PurposeThe aim of this study is to assess the utility of targeted, framed, efficacy-enhancing messages on calcium consumption from dairy in adults aged 30–50 in a randomized controlled trial.MethodSeven hundred and thirty-two individuals (463 women, 269 men; Mage = 40.57 years) were randomly assigned to one of five message conditions: (1) gain-framed (GF), (2) loss-framed (LF), (3) self-regulatory efficacy-enhancing (SRE), (4) GF plus SRE (GF + SRE), or (5) LF plus SRE (LF + SRE). Conditions were separate for men and women. Each condition received an emailed message on four consecutive days. Calcium intake from dairy, self-regulatory efficacy, outcome expectations, and outcome value were measured at baseline, 1 and 4 weeks following the intervention.ResultsCalcium intake from dairy significantly increased from baseline to week 1 post-intervention in all conditions (p < .001). A significant message condition x time interaction (p = .04) revealed that increases seen in the LF + SRE condition were maintained at week 4. All social cognitive constructs increased following the intervention (ps < .01). Self-regulatory efficacy (β = .28, p < .01) and outcome expectations (β = .19, p < .01) were significant predictors of subsequent calcium intake (week 4) from dairy.ConclusionTaken together, it appears as though ensuring message content is targeted to the specific population’s beliefs and motives is of importance when developing behavioral change intervention material.