Psychosocial predictors of diet and physical activity in African-Americans: results from the Delta Body and Soul effectiveness trial, 2010-2011.

PURPOSE
To examine associations among psychosocial constructs of behavior change and postintervention changes in diet and physical activity (PA).

DESIGN
Quasi-experimental with cluster (church) treatment assignment.

SETTING
Churches (n = 8) in a rural, southern region of the United States.

SUBJECTS
A total of 403 African-American adults participating in the Delta Body and Soul study.

INTERVENTION
Six-month diet and PA intervention consisting of monthly didactic educational sessions with specific emphasis on increasing consumption of fruits, vegetables, and whole grains, and decreasing consumption of added sugars. Self-directed PA was promoted throughout the intervention.

MEASURES
Validated surveys for all dietary, PA, and psychosocial measures.

ANALYSIS
Secondary analysis using generalized linear mixed models to test for significant intervention effects on psychosocial constructs and for significant associations between changes in psychosocial constructs and changes in diet and PA outcomes after controlling for covariates.

RESULTS
Intervention effects were apparent for several dietary psychosocial constructs (improvements ranging from .5 to 2.0 points), but only one PA construct (decisional balance for exercise). Changes in psychosocial constructs, including self-efficacy, social support, and decisional balance, were significant predictors of dietary outcome changes (model coefficients ranging from .03 to .42), but not PA changes.

CONCLUSION
Understanding which psychosocial constructs predict improvements in dietary and PA behaviors helps inform theoretical mechanisms of action and identify social and behavioral processes to target in faith-based interventions.