Iris Kanera

148 Chapter 6 evaluated web-based interventions, which aimed to improve a healthy diet among the general population (Kohl et al., 2013). Furthermore, in populations with various chronic diseases, the majority of dietary interventions reported no statistically significant effects on dietary behavior after 12 months, even when significant short-term effects were found (Desroches et al., 2013). Bluethmann et al. (2015) acknowledged that the cancer diagnosis might possibly provide a teachable moment for adopting a healthy diet, however they demonstrated that vegetable consumption continued to deteriorate as more time passes since the diagnosis. The KNW respondents started using the KNW in a period that can be considered as a teachable moment (around six months after completing primary cancer treatment). During the duration of the present study, the effect of the teachable moment may have become weaker, considering the improvements in fatigue and depressive symptoms among the IC within six months (Willems et al., 2016). This might possibly explain the overall decrease in vegetable consumption throughout the 12-month follow-up period. In sum, the vegetable consumption of the KNW users did not sustainably improve, while a healthy dietary pattern in combination with sufficient physical activity can have a positive impact on bodyweight, comorbidities, and QoL (Bruno et al., 2016; Koutoukidis et al., 2015; Tsilidis et al., 2016). To achieve sustained increases in vegetable consumption among cancer survivors, more intensive and prolonged support might be required (Christy et al., 2011; Ottenbacher et al., 2012; von Gruenigen et al., 2008). The changes in moderate PA and vegetable consumption within the first six months of the study might be initiated by applying behavior change methods that target specific determinants that derive from social cognitive theories and behavior change models (Ajzen, 2011; Baumeister et al., 1994; de Vries et al., 2003). In their systematic review of behavior theories, Kwasnicka et al. (2016) described explanations how individuals maintain behavior changes over time, in different contexts, and including the risk of a potential lapse to the prior behavior. According the authors, relevant theoretical concepts for behavior change maintenance are maintenance motives, self-regulation, psychological and physical resources, habits, and environmental and social influences. While active self-regulation is needed to initiate behavior change, conscious self-regulation may decrease and the behavior might become more habitual and effortless with repeated performance. In the present study, different cultural and environmental influences might have influenced behavior maintenance concerning moderate PA and vegetable consumption. In the Netherlands, the level of engagement in physical activity is generally high (Loyen et al., 2016), while the consumption of vegetables in the general Dutch population is low and might be difficult to change (Geurts, Beukers, van Rossum, 2013; National Institute for Public Health and Environment, 2016). This fully automated KNW might be appropriate to serve as a first step in a stepped care approach within cancer aftercare. Personalized broad-scoped support can be widely