Closing the knowledge-behavior gap in health promotion: the mediating role of self-efficacy.

Three cross-sectional data waves spanning 10 years (N = 2,055; 2,026; and 2,068) and 2 longitudinal data waves spanning 4 years (N = 1,384 and 1,151) from the Stanford Five-City Project (see Farquhar, Fortmann, Maccoby, & Haskell, 1985, for a full description of the project) were analyzed to determine whether diet self-efficacy mediated the relation between diet knowledge and behavior. In the cross-sectional data waves, knowledge-behavior correlations were greater among those with high (compared to low) self-efficacy. In the longitudinal data waves, knowledge-behavior correlations increased among those who increased their self-efficacy and decreased among those who decreased their self-efficacy. Recommendations are made for public health campaigns designed to improve individuals' health behaviors.