Differential effects of planning and self-efficacy on fruit and vegetable consumption.

To change dietary behaviors, people must be motivated to do so. But intentions often do not translate into behavior. Strategic planning (as a mediator) is expected to move people from intention to action. However, individuals who lack perceived self-efficacy might fail to apply their plans when encountering challenging situations. Thus, self-efficacy might operate as a moderator variable when it comes to studying the mediator effects of planning on behaviors. This study examines the interactive role of planning and self-efficacy in the context of dietary changes. A longitudinal sample of 411 employees was surveyed twice in terms of their fruit and vegetable consumption over a 4-week interval. Intentions, planning, and fruit and vegetable consumption were specified as a mediator chain with self-efficacy as a moderator at two stages of the putative change process. Baseline behavior served as a covariate in the model. Intentions were translated into dietary behavior by planning. Self-efficacy moderated this mediation at the second stage, reflected by a planning x self-efficacy interaction on fruit and vegetable consumption. The strength of the mediated effect increased along with levels of self-efficacy. Individuals with very low self-efficacy did not benefit from planning. If a person lacks self-efficacy, planning does not seem to translate intentions into fruit and vegetable consumption.