Johannes Brug

Parenting style and adolescent fruit consumption

The importance of the social environment for dietary behaviour has been highlighted in the past decade. A type of environmental influence that has received increasing research attention in recent years is the influence that parents can have on their childrens dietary behaviour through food-related parenting practices. Much of the work done so far, however, has reported inconsistent findings and poorly understood mechanisms of influence. The present study aimed to explore the possible environmental influence of general parenting style on adolescent food choice patterns. Data were collected at schools (N=643; mean age 16.5 years), using self-administered questionnaires on parenting style, fruit intake behaviour and fruit-specific cognitions. Consistent and theoretically predictable differences were found between adolescents who described their parents as authoritative, authoritarian, indulgent or neglectful. Fruit consumption and fruit-specific cognitions were most favourable among adolescents who were being raised with an authoritative parenting style. Children of parents with indulgent parenting styles consumed more fruit than adolescents from authoritarian or neglectful homes. Consequences of these results for the interpretation of earlier studies on the influence of parenting practices are discussed, and a research model is proposed for future studies of parental influences on adolescent dietary behaviours.

Past, present, and future of computer-tailored nutrition education

Computer-tailored nutrition education is an innovative and promising tool to motivate people to make healthy dietary changes. It provides respondents with individualized feedback about their dietary behaviors, motivations, attitudes, norms, and skills and mimics the process of person-to-person dietary counseling. The available evidence indicates that computer-tailored nutrition education is more effective in motivating people to make dietary changes than general nutrition information, especially for reduction of dietary fat. The effectiveness of computer tailoring has been attributed to the fact that individualized feedback commands greater attention, is processed more intensively, contains less redundant information, and is appreciated better than more general intervention materials. Interactive technology (eg, the Internet, the World Wide Web) offers good opportunities for the application of computer-tailored nutrition education, and a first controlled study of Web-based computer tailoring shows promising results. However, using the Web for interactive personalized nutrition education also presents new challenges.

Misconceptions of Fruit and Vegetable Consumption: Differences between Objective and Subjective Estimation of Intake

Abstract This study reports the discrepancy between two methods to assess fruit and vegetable consumption in a Dutch adult population (N = 367). The consumption of fruit and vegetables was assessed by telephone interviews in two ways: it was estimated objectively by using a food frequency method (the number of grams of fruit and vegetables that subjects ate every day), and it was estimated subjectively by assessing the self-rated fruit and vegetable intake of subjects. Besides behavior, intention was measured in two ways: the intention to eat fruit and vegetables each day and the intention to eat more fruit and vegetables. Also, determinants were measured using a theoretical model including the attitude toward fruit and vegetable consumption, self-efficacy expectation, and the social influence to eat fruit and vegetables. Results show that there were large differences between the self-rated and estimated objective consumption of fruit and vegetables. Subjects rated their own intake as much higher than their estimated objective intake. Furthermore, multiple regression analyses show that the determinants predicted the self-rated consumption much better than the estimated objective consumption. Subjects who rated their own consumption as high had more positive beliefs concerning fruit and vegetable consumption, experienced more positive social influence to eat fruit and vegetables, and had higher self-efficacy expectations of being able to eat fruit and vegetables than subjects who rated their own consumption as low. It is concluded that nutrition education aimed at stimulating fruit and vegetable consumption should especially focus on making people aware of their own fruit and vegetable intake, in addition to changing attitudes and self-efficacy expectations.

Why do adolescents eat what they eat? Personal and social environmental predictors of fruit, snack and breakfast consumption among 12-14-year-old Dutch students.

OBJECTIVEnThe aim of the study was to investigate the relative importance of personal and social environmental predictors of the consumption of fruit, high-fat snacks and breakfast.nnnDESIGNnA school-based cross-sectional survey. Data were collected through written questionnaires.nnnSETTINGnStudents from eight schools in the southern part of The Netherlands.nnnSUBJECTSnSix hundred and one students from preparatory secondary vocational education schools.nnnRESULTSnAbout a quarter of the variation in actual behaviours and intentions to change the behaviours could be explained. Stepwise multiple regression analysis revealed that, for all three behaviours, higher intention to change was especially associated with a more positive attitude and subjective norm, and higher intentions to increase fruit intake with more positive self-efficacy expectations. With regard to actual consumption, a more positive attitude towards eating fruit was the only significant correlate of a higher consumption of fruit. A more positive attitude towards eating high-fat snacks, perceived lower intake of the mother, and higher food availability and accessibility were associated with consumption of high-fat snacks, and a more positive attitude to breakfast more frequently was associated with more frequent breakfast consumption.nnnCONCLUSIONnThe results indicate that adolescents attitudes are the most important determinants of different health-related eating behaviours and intentions to change. Interventions promoting a healthy diet for adolescents should include creative strategies to achieve positive associations with healthy dietary changes.

The internet and nutrition education: challenges and opportunities.

Objective:To review the possibilities of using the Internet and especially the World Wide Web (WWW) in nutrition education.Results:A healthy existence is partly dependent on dietary behaviours. One way to promote health-promoting dietary habits is nutrition education. In the last decades several potentially important new channels for health communication and nutrition education have emerged, with the Internet and its WWW as the most striking example. The introduction and growth of the WWW has enabled swift and inexpensive distribution of nutrition education expertise and materials. Furthermore, the WWW has also been used for tailoring nutrition education to the personal characteristics of the user. Only few studies have investigated the effects of generic web-based nutrition education, while web-based computer-tailored nutrition education has been studied in randomised controlled trials, with promising but mixed results. Two important challenges for web-based nutrition education interventions are to realise sufficient exposure and to ensure sufficient source reliability and credibility.Conclusions:Next to the great opportunities, there are many challenges for web-based nutrition education. Some evidence for effects of web-based computer-tailored nutrition education has been reported, but more research is needed to obtain evidence for the effectiveness in real-life situations.Sponsorship:The contribution of WK was made possible by a grant from ZonMw, The Netherlands Organisation for Health Research and Development; the contribution of AO was made possible by a grant from the Netherlands Heart Foundation.

An Exploration of Factors Related to Dissemination of and Exposure to Internet-Delivered Behavior Change Interventions Aimed at Adults: A Delphi Study Approach

Background The Internet is an attractive medium for delivering individualized, computer-tailored behavior change interventions to large numbers of people. However, the actual numbers of people reached seem to fall behind the high expectations. Insight into factors that determine use of and exposure to these Internet interventions is important to be able to increase the reach and improve exposure. Objective The aim was to identify potentially important factors that determine whether adults visit an Internet-delivered behavior change intervention, extend their visit, and revisit the intervention. Methods A systematic, three-round Delphi study was conducted among national and international experts from Internet intervention research and practice, e-marketing/e-commerce, Web design, and technical website development. In the first round, 30 experts completed a structured, open-ended online questionnaire assessing factors that were, in their opinion, important for a first visit, an extended visit, a revisit and for effective promotion strategies. Based on the responses in this first questionnaire, a closed-ended online questionnaire was developed for use in the second round. A total of 233 experts were invited to complete this questionnaire. Median and interquartile deviation (IQD) scores were computed to calculate agreement and consensus on the importance of the factors. The factors for which no consensus was obtained (IQD > 1) were included in the third-round questionnaire. Factors with a median score of six or higher and with an IQD ≤ 1 were considered to be important. Results Of the 62 experts invited for the first round, 30 completed the questionnaire (48% response rate); 93/233 experts completed the second-round questionnaire (40% response rate), and 59/88 completed the third round (67% response rate). Being motivated to visit an Internet intervention and perceiving the intervention as personally relevant appeared to be important factors related to a first visit. The provision of tailored feedback, relevant and reliable information, and an easy navigation structure were related to an extended visit. Provision of regular new content and the possibility to monitor personal progress toward behavior change were identified as important factors to encourage a revisit. Primarily traditional promotion strategies, like word-of-mouth by family and friends, a publicity campaign with simultaneous use of various mass media, and recommendation by health professionals, were indicated as effective ways to encourage adults to visit an Internet intervention. Conclusions This systematic study identified important factors related to the dissemination of and exposure to Internet interventions aimed at adults. In order to improve optimal use of and exposure to Internet interventions, potential users may need to be motivated to visit such an intervention and the information provided needs to be personally relevant. Furthermore, several (technical) aspects of the intervention itself need to be taken into account when developing Internet interventions.

Internet-delivered interventions aimed at adolescents: a Delphi study on dissemination and exposure

It appears that in practice exposure to Internet-delivered behaviour change interventions, encouraging a healthy lifestyle for adolescents with regard to health risk behaviours, is quite low. There is, however, a lack of evidence-based insight into how to disseminate such interventions and how to reach optimal exposure. A more extensive exploration is therefore timely since this knowledge is crucial to improve the public health impact of such interventions. By means of a three-round Delphi study factors associated with dissemination of and exposure (first visit, stay long enough and revisit) to Internet-delivered interventions aimed at adolescents had been identified, as well as the extent to which experts agree on the importance of these factors. Results showed that there was a high rate of consensus among experts from several disciplines with regard to the importance of factors like word of mouth recommendation, the interface of the intervention and utilization of all features provided by the Internet. Experts do not agree, however, on a gold standard for successful dissemination. Overall, the results of this exploration serve as a handle for the formation of further research questions to be tested and answered in research among adolescents.

Clustering of energy balance-related behaviours and their intrapersonal determinants

The consistent increase in the prevalence of obesity that currently occurs in industrialised countries can be explained by the existence of multiple behavioural actions that exert continuous pressure toward a positive energy balance. The present study examined the clustering of intrapersonal determinants of five energy balance-related behaviours (i.e., consumption of energy-dense snacks, the use of high-fat sandwich fillings, fruit consumption, active transport and physical activity during leisure time). The research population consisted of a large sample of Dutch adolescents (nu2009=u20093859; mean age 14.8; 55.2% girls). Attitude, subjective norm, perceived behavioural control and intention measures related to the various behaviours clustered more strongly than the behaviours themselves, with correlations ranging from 0.09 to 0.55. The consequences of adopting an energy balance approach are discussed.

Cognitive determinants of energy balance-related behaviours : measurement issues

The burden of disease as a result of overweight and obesity calls for in-depth examination of the main causes of behavioural actions responsible for weight gain. Since weight gain is the result of a positive energy balance, these behavioural actions are referred to as ‘energy balance-related behaviours’ (EBRBs). In the broadest sense, there are only two EBRBs: food intake and physical activity. However, both diet and physical activity are complex behavioural categories that involve a variety of actions. This article discusses the potential problems and opportunities related to the assessment of cognitive determinants of energy intake and energy expenditure behaviours.We argue for the necessity of studying determinants of EBRBs within an energy balance approach, i.e. focusing on energy input as well as output, instead of only studying dietary change or physical activity behaviour. As a result, however, theoretically sound questionnaires assessing determinants of EBRBs are likely to annoy respondents. It is especially the measurement of the behaviours and the use of belief-based constructs that cause questionnaires to be long, which may lead to low response rates and invalid data.In this article, we propose a careful and systematic consideration of the inclusion or exclusion of measures of cognitive determinants. First, if studies show that an EBRB is strongly influenced by environmental factors and is not or only to a minor extent under intentional control, measurement of cognitions is of little use. Second, only when we have proof that attitudes, norms and perceived behavioural control predict intentions, should we aim to assess the underlying beliefs. Third, since assessment of beliefs results in similar or better prediction than using belief-valuation combinations, we should not ‘annoy’ respondents with valuation items. Finally, we argue that the traditional paper-and-pencil survey is still the most reliable and practical data collection method. However, pilot studies applying computerised adaptive methods to determinants of EBRBs are encouraged.

Differences in use and impact of computer-tailored dietary fat-feedback according to stage of change and education

Computer-tailored written nutrition education has been found to be more effective in motivating people to reduce their consumption of fat than traditional written information. The present study aimed to test whether this innovative nutrition education intervention is also suitable for people with low motivation to change and low education among a self-selected sample of 699 adults. Computer-tailored feedback proved to be more effective in motivating precontemplators to proceed towards fat reduction than general information. Higher appreciation and use of the computer-tailored fat-feedback was found among respondents in contemplation than in other stages. No difference in impact of computer-tailored fat-feedback on fat intake was found between educational groups. Respondents with low education were more positive about how interesting and how personally relevant the tailored letters were. It was concluded that printed computer-tailored fat-feedback can be applied successfully to motivate precontemplators and people with low education to (consider to) reduce their fat intake.