Perceived Self-Efficacy in Health Behaviour Change The Construct of

Spivak, Kwon & Schwarzer, 2007; Scholz et al., 2005; Schwarzer, Luszczynska, Ziegelmann,
Scholz, & Lippke, 2008).
Self-Efficacy in Dietary Behaviour Change: Two Studies
Perceived self-efficacy is supposed to act as a mediator or as a moderator between
intentions and behaviours. Studies are needed to examine the mechanisms that might play a
role in different contexts for different samples and different health behaviours. Study I aims at
improving dietary self-efficacy and at comparing such self-efficacy interventions with a
planning intervention.
Our general assumption is that people need a minimum level of perceived self-efficacy for
most processes of health behaviour change. Thus, self-efficacy may serve as a moderator of
various mediating processes. Study II analyzes whether coping planning (mediator variable)
mediates the effect of intentions (independent variable) on dietary behaviour (dependent
variable) as a function of self-efficacy levels (moderator).
Study I: Improving Fruit and Vegetable Consumption: A Self-Efficacy Intervention
Compared to a Combined Self-Efficacy and Planning Intervention
Effects of interventions targeting self-efficacy alone or combined with action plans were
examined in the context of fruit and vegetable consumption (Luszczynska, Tryburcy, &
Schwarzer, 2007). E-mail messages were sent to a self-efficacy group, a combined selfefficacy
and action planning group, and a control group. At a 6-month follow-up, 200 adults
reported their fruit and vegetable consumption, along with current levels of self-efficacy and
planning. The two experimental groups gained equally from the interventions, as documented
by changes in behaviour (see Figure 1). In both intervention groups, change in respective
cognitions predicted change in fruit and vegetable consumption.
Figure 1. Changes in fruit and vegetable consumption in two intervention groups and the
control group