Iris Kanera

162 Chapter 7 Use of the behavior-specific module (respectively PA – Diet) was not significantly related to increases in moderate PA and diet behavior. The behavioral changes may be caused by a combined usage of KNW elements (i.e., MRA, other modules, news items, and forum), which might have led to synergistic, mutually reinforcing effects. Which of the KNW elements may have facilitated the positive changes in moderate PA and diet behavior is not yet clear. To gain further insights into the relationships of different usage patterns with outcomes, additional analyses are required. We provide two possible explanations for the initial increase and subsequent lack of sustained effect on vegetable consumption. First, the moment of cancer diagnosis is often considered a teachable moment. Prior studies confirmed that early cancer survivors were more likely to meet the vegetable and fruit recommendations as compared to long-term survivors (Bluethmann et al., 2015; LeMasters et al., 2014). This might explain the increase in vegetable consumption in both the intervention group and control group after six months. Besides, access to the KNW could have had an additional effect on vegetable consumption in the intervention group. However, given the decrease of vegetable consumption after 12 months in both study groups, this “teachable moment-effect” appeared to fade over time. This might imply that the KNW was not sufficiently powerful to maintain the positive changes in vegetable consumption in the intervention group in the long-term. Second, maintaining diet change is difficult. The complexity of vegetable consumption consists of a set of many separate behaviors, for example, buying, preparing, and eating (different types of ) vegetables (Bogers et al., 2004a). When healthy diet behavior has been adopted, it could become increasingly effortful for individuals to maintain self-regulation strategies aimed at maintenance of several behaviors related to vegetable consumption, besides coping with various tempting situations (Kwasnicka et al., 2016). According to the Self-regulation Theory, willpower and self-control include conscious self-regulation that is dependent upon restricted mental resources that can become depleted (Baumeister et al., 1994). Directly after receiving the MRA, participants’intention to eat more vegetables might be influenced by conscious deliberation. Optimally, the new behavior should become more automatic and the need for conscious self-regulation should therefore decrease over time, which is less energy consuming. Apparently, a higher vegetable consumption has not become a new habit among KNW participants after 12 months, suggesting that barriers (e.g., lack of willpower, lack of time to prepare healthy foods, unhealthy dietary habits of partners, and costs of and difficulty accessing healthy food) outweighed motivation, as observed by Coa et al. (2015). A direct comparison with similar programs tested in a RCT is not possible. Some studies are ongoing or in the pilot testing stage (De Cocker et al., 2015; Krebs et al., 2017; Lee et al., 2014). “Comparable” interventions by for instance Bantum et al. (2014) and Mc Carrol et al. (2015) including in-person contact and targeting lifestyle and/or psychosocial issues,