Make Better Choices (MBC) - Multiple Behavior Change in Diet and Activity

Poor quality diet and physical inactivity are the most prevalent, preventable causes of death in the United States. In particular, high saturated fat diet (Fat), low fruit and vegetable intake (FV), low physical activity (PA), and high sedentary leisure screen time (Sed) co-occur and heighten the risks of cardiovascular disease and cancers. The first Make Better Choices (MBC1) experiment contrasted four strategies to promote healthful change across these four risk behaviors. Each intervention targeted two behaviors (one diet, one activity) simultaneously and either increased healthy or decreased unhealthy responding. The intervention targeting increased FV and decreased Sed was most efficacious, yielding unexpectedly sustained improvement in three out of the four risk behaviors (FV, Sed, Fat). The proposed MBC2 trial tests the efficacy of MBC intervention to promote sustained, healthful change in diet and activity at 6 and 12 months, as contrasted with a stress management control condition. MBC2 tests competing hypotheses about the optimal way to increase PA without undermining the maintenance of FV, Sed, and Fat by changing multiple behaviors either sequentially or simultaneously. Furthermore, MBC2 examines mediators and biomarkers of healthy lifestyle change. Community dwelling adults (N=250) with suboptimal diet and inactive lifestyle will be randomized to the following conditions: 1) Sequential MBC (increasing FV intake and decreasing Sed, followed by increasing PA), 2) Simultaneous MBC (increasing FV, decreasing Sed, and increasing PA), or 3) Control (stress management). Participants in all conditions will use Smartphones equipped with customized behavioral decision support tools to self-monitor health behaviors. These handheld devices will be programmed to automatically transmit these data to our study server to be reviewed by a personal behavior coach. Based on theories of self-regulation and habit strength, the Mastery hypothesis predicts superior health behavior change for participants randomized to the sequential condition. It is anticipated that these effects will be mediated by greater habit strength for healthy eating and physical activity. However, based on goal systems theory, the Synergy hypothesis predicts superior health behavior change among participants randomized to the simultaneous condition. It is anticipated that these effects will be mediated by the establishment of superordinate healthy lifestyle goals. The results of the MBC2 trial will assist researchers in understanding the optimal manner in which to facilitate multiple health behavior change in this population. Furthermore, these data will help to identify the mechanisms that underlie healthy change among prevalent risk behaviors. If successful, this trial will also result in an innovative, highly disseminable technology-supported minimal counseling intervention to address the American unhealthy diet and sedentary lifestyle.