Emely de Vet

Does habit strength moderate the intention-behaviour relationship in the Theory of Planned Behaviour? The case of fruit consumption

The present study examined if habit strength moderated the influence of intention on fruit consumption in a Dutch adult sample (N = 521, 46.3% males, mean age = 34.50, SD = 10.87), using the theoretical relations of the Theory of Planned Behaviour (TPB). TPB variables and habit strength were assessed at baseline. Fruit consumption was assessed with a validated questionnaire five weeks later. Three groups were created: low habit strength (n = 180), medium habit strength (n = 185) and high habit strength (n = 156). Confirmatory factor analyses and multi-group path analyses were performed using AMOS 4.0. A good fit was obtained for the overall measurement model and the structural models. Multi-group path analyses showed that intention was a significant predictor of fruit consumption in the low habit (β = 0.36, p < 0.001) and medium habit group (β = 0.30, p < 0.001), but a non-significant predictor in the high habit group (β = 0.05, p = 0.596). Implications for information-based and motivation-based interventions are discussed.

Minority talks: The influence of descriptive social norms on fruit intake

Previous research established that norms describing the behaviour of a majority (e.g. ‘many people consume too much alcohol’) can have ironic and unwanted effects on health behaviour. To date, no research has addressed the effects of minority descriptive norms (e.g. ‘only few people use sunscreen’), while such minority norms are frequently communicated to the public. The current studies investigate the effects of minority and majority norms on intended and actual fruit intake. University students received either minority or majority normative information describing fruit intake behaviour of a referent group. Identification strength with this referent group was measured (Study 1) or manipulated (Study 2). Results showed that, compared to majority norms, minority norms negatively affected fruit intake when participants strongly identify with the referent group. Moreover, absolute negative (minority norm) and positive (majority norm) effects of one-third portion of fruit were found compared to a no-norm condition. Since minority norms are often communicated with the intention of alarming people regarding their low engagement in health protective behaviour, the potential ironic effects of these minority norms should be taken into account when presenting such information to the public.

Determinants of forward stage transition from precontemplation and contemplation for fruit consumption.

Purpose. To examine associations between decisional balance, self-efficacy, fruit intake, and stage of change transition from precontemplation and contemplation with cross-sectional and longitudinal methods. Design. A longitudinal cohort study with the use of electronic questionnaires was conducted. Three measurements were analyzed cross-sectionally, and the two intervals between the measurements were analyzed longitudinally. Setting. A random sample of 1500 individuals from an existing Dutch Internet panel resulted in a cohort of 735 individuals. Of the cohort, 648 (response rate 88%), 592 (response rate 81%), and 570 (response rate 78%) respondents completed questionnaires at the start of the present study (T1), 53 days after T1 (T2), and 106 days after T1 (T3), respectively. Subjects. Mean age was 37.5 years, 51% were women, and 57% ate less than the recommended intake of 250 g of fruit per day. Measures. Questionnaires included items measuring stage of change, factors favoring (pros) or working against (cons) behavior change, and self-efficacy. A food frequency questionnaire was used to assess fruit intake. Results. Logistic regression analyses showed that pros, fruit intake, and self-efficacy predicted forward stage transition from precontemplation. Self-efficacy predicted forward stage transition from contemplation. Cons did not predict stage transitions. Results from longitudinal analyses were similar to cross-sectional results, except for self-efficacy: no differences between early stages in self-efficacy were found, whereas self-efficacy predicted these early stage transitions. Conclusions. Within the limitations posed by the sampling frame, results provided support for the Transtheoretical Model, although determinants might not always be stage specific.

Do distant foods decrease intake? The effect of food accessibility on consumption.

Objective: Two studies examined the hypothesis that making snacks less accessible contributes to the regulation of food intake. Study 1 examined whether decreasing the accessibility of snacks reduces probability and amount of snack intake. The aim of Study 2 was to replicate the results and explore the underlying mechanism in terms of perceived effort to obtain the snack and perceived salience of the snack. Methods: In Study 1 (N = 77) and Study 2 (N = 54) distance to a bowl of snacks was randomly varied at 20, 70 or 140 cm in an experimental between-subjects design. Main outcome measures were the number of people who ate any snacks (probability of snack intake), the amount of snacks consumed and risk of compensatory behaviour as measured by food craving. In Study 2, self-report ratings of salience and effort were examined to explore potential underlying mechanisms. Results: Study 1 showed lower probability and amount of intake in either of more distant conditions (70 and 140 cm) compared to the proximal condition (20 cm), with no unintended effects in terms of increased craving. Study 2 replicated the results of Study 1 and showed that distance affected perceived effort but not salience. Conclusions: Making snacks less accessible by putting them further away is a potentially effective strategy to decrease snack intake, without risk of compensatory behaviour.

The Transtheoretical model for fruit, vegetable and fish consumption: associations between intakes, stages of change and stage transition determinants

BackgroundCardiovascular diseases are caused by multiple behavioral factors, including different dietary factors. We examined to what extent fruit, vegetable and fish consumption are related, and whether behavioral determinants vary across these dietary behaviors from a Transtheoretical model perspective.MethodsData were collected among 1142 participants (T0; response rate 46%) selected from an Internet panel, who were followed-up one-week later (T1; N = 1055, response rate 92%). Mean age was 35.4 (SD = 11.9) years, 35% was male, and most respondents were of Dutch origin (90%). Of the respondents, 13%, 44% and 43% had a low, medium or high level of education, respectively. Electronic questionnaires assessed fruit, vegetable and fish intake (food frequency questionnaires), stages of change, decisional balance and self-efficacy, for each of these three behaviors.ResultsStages of change and (changes in) fruit, vegetable and fish intake were only weakly associated; decisional balance and self-efficacy were more strongly associated. Some presumed predictors of stage transitions were similar for fruit, vegetable, and fish intake, i.e., strong pros predicted progress out of precontemplators and low self-efficacy predicted relapse from action/maintenance for all behaviors. However, progress out of contemplation and out of preparation showed different patterns for fruit, vegetable and fish intake.ConclusionThe weak associations between intakes and potential determinants for fruit, vegetable, and fish consumption do not warrant an integrated dietary change approach targeting the same determinants for each behavior.

Implementation intentions for buying, carrying, discussing and using condoms: the role of the quality of plans

Forming implementation intentions (i.e. action plans that specify when, where and how a person will act) could be effective in promoting condom use on a large scale. However, the technique implies that people are able to form high quality implementation plans that are likely to induce behaviour change. Young single females, aged 16-30 years old, were asked to form either an implementation intention for the target behaviour using condoms (n = 159) or preparatory implementation intentions for buying, carrying, discussing and using condoms (n = 146). Condom preparations were assessed at follow-up 2 months later. The implementation intentions that participants formed were rated on quality. In general, it appeared hard for young women to form high quality general implementation intentions for the target behaviour condom use. Implementation intentions for the preparatory behaviours were of better quality than general implementation intentions. Females who formed strong implementation intentions in the preparatory behaviours condition were more committed to these plans and perceived them as more useful. Plan commitment and perceived usefulness predicted condom preparations at follow-up. We conclude that it is important to ask individuals to form implementation intentions for the preparatory behaviours rather than for the target behaviour alone.

Access to excess: how do adolescents deal with unhealthy foods in their environment?

PURPOSE Easy access to unhealthy foods is believed to contribute to the current overweight epidemic. It remains unclear, however, how access to unhealthy foods is related to self-regulation of food intake. This study tests the hypothesis that using self-regulation strategies buffers the negative influences of easy access to unhealthy foods. METHODS Cross-sectional survey data from 2764 adolescents aged 10-17 years from four European countries (The Netherlands, UK, Poland and Portugal) about use of self-regulation strategies, access to unhealthy foods and intake of unhealthy foods (sweet and salty snacks and sugar-sweetened beverages) were used. RESULTS Both access to unhealthy foods and use of self-regulation strategies were independently, but in opposing directions, related to intake of unhealthy foods. Easy access to unhealthy food products was associated with higher consumption, but this effect could be attenuated by use of self-regulation strategies to facilitate healthy eating even when the food environment tempts one to do otherwise. CONCLUSIONS Health promotion policy and programs should not only address the food environment but could also teach young people better strategies to deal with it.

Stages of change in fruit intake: A longitudinal examination of stability, stage transitions and transition profiles

The present study examined stability and transitions in Transtheoretical stages of change for fruit intake in an adult cohort of 735 individuals not exposed to a planned intervention. Six assessments took place within a four-month period with varying time intervals using electronic questionnaires, measuring fruit intake, stage of change and demographic characteristics. Precontemplation and maintenance were the most stable stages of change, while preparation was the least stable. Longer time intervals showed lower stability, but frequent stage transitions also occurred in shorter time intervals. Seven transition profiles were distinguished. Sequences within transition profiles mostly showed stage transitions to adjacent stages, independent of the interval duration. Differences in fruit intake, age, level of education and ethnicity were found between different transition profiles. Stability rates and most transition sequences largely support the Transtheoretical Model. Results indicating potential deviations from the model, e.g. short-term stage instability and stage transition profiles not in accordance with the Transtheoretical Model are discussed.

Identifying the ‘if’ for ‘if-then’ plans: Combining implementation intentions with cue-monitoring targeting unhealthy snacking behaviour

Implementation intentions aimed at changing unwanted habits require the identification of personally relevant cues triggering the habitual response in order to be effective. To facilitate successful implementation intention formation, in the present study, planning was combined with cue-monitoring, a novel way to gain insight into triggers for unhealthy snacking. It was tested whether keeping a cue-monitoring diary and tailoring implementation intentions accordingly improves plan effectiveness. A 2 Monitoring (cue-monitoring, control) × 2 Planning (implementation intention, goal intention) between subjects design was adopted. Participants (N = 161) monitored their unhealthy snacking behaviour for a week using either a cue-monitoring or a control diary. Participants then formulated a goal intention or an implementation intention tailored to their personal cue. Snacking frequency and caloric intake from unhealthy snacks were examined using a seven-day snack diary. The results did not indicate an interaction but yielded a main effect of Monitoring. Cue-monitoring either or not combined with implementation intentions reduced unhealthy snacking behaviour compared with control. Findings emphasise the effectiveness of cue-monitoring, suggesting that on the short term, cue-monitoring suffices to decrease unhealthy snacking, without additional benefit from planning. Future research should examine whether supplementing cue-monitoring with implementation intentions is required to establish long-term behaviour change maintenance.

When the going gets tough, who keeps going?: Depletion sensitivity moderates the ego-depletion effect

Self-control relies on a limited resource that can get depleted, a phenomenon that has been labeled ego-depletion. We argue that individuals may differ in their sensitivity to depleting tasks, and that consequently some people deplete their self-control resource at a faster rate than others. In three studies, we assessed individual differences in depletion sensitivity, and demonstrate that depletion sensitivity moderates ego-depletion effects. The Depletion Sensitivity Scale (DSS) was employed to assess depletion sensitivity. Study 1 employs the DSS to demonstrate that individual differences in sensitivity to ego-depletion exist. Study 2 shows moderate correlations of depletion sensitivity with related self-control concepts, indicating that these scales measure conceptually distinct constructs. Study 3 demonstrates that depletion sensitivity moderates the ego-depletion effect. Specifically, participants who are sensitive to depletion performed worse on a second self-control task, indicating a stronger ego-depletion effect, compared to participants less sensitive to depletion.