Page 129 - ON THE WAY TO HEALTHIER SCHOOL CANTEENS - Irma Evenhuis

more comprehensively: in the longer term, and on different groups of students. To be able to measure the sustainability of the effects throughout adolescence, the duration of such a study should be at least three years.
Research into potential differences of the effect of a healthier canteen in different student groups is recommended. Firstly, this should consider students of different age groups because on the one hand, students from higher classes have experienced the old as well as the new offering in the canteen, while those in the lower classes have experienced only the healthier canteen. This will also enable investigation of differences in effect between younger (12-14) and older (15-18) adolescents [210]. Second, although our study did not reveal gender differences in purchase behaviour in the school canteen, it did find subtle gender differences, with boys indicating buying food and drinks outside the school more often. This makes further investigating these differences worthwhile, because other studies did find differences [187]. Thirdly, the effect of a healthier canteen on students with different educational levels is of interest.
The school is known to be just one of the settings where students buy and take food and drinks. Since our study confirms that youth also bring food from home and buy food outside the school, it is therefore of interest to investigate the relation between the exposure of healthier foods in schools and food choices outside school throughout the day. Such research should assess students’ daily food intake in the long-term, as well as the locations where they buy and eat foods and drinks during the day [49].
One reason for also assessing students’ dietary behaviour outside school is the risk of compensatory behaviour outside school in response to the offer of healthy products at
school [37, 49]. A second reason is that the healthy school canteen is likely to communicate
a descriptive norm, which could influence students’ food choices outside school: if 7 students see healthy products in school, they may assume that other students also buy
these foods and that it is normal to eat those kinds of foods. This may result into a positive change in students’ food choices outside school throughout the day and later in life [192, 218]. Besides to the assessment of student dietary behaviour in the physical environment in- and outside school, insight into other factors related to what adolescents eat is also necessary. As Figure 7.1 shows, these may include individual factors, such as age, ethnicity or behavioural determinants, or social environments, such as social norms and support from parents and friends [19, 20, 41].
Although investigating students’ dietary behaviour over a longer period and throughout the day may be complex, new technologies like Ecological Momentary Assessment (EMA) may increase the feasibility of such measurements [195, 219]. EMA uses repeated data collections, of people’s current behaviour and experiences in their daily life. For example, a mobile phone application enables students to receive questions about what they eat, with whom and where, every 2-hour. EMA may be particularly feasible for students because they are used to integrating their mobile phones into their daily activities. In addition, existing tools to report daily intake can also be used, for example “Mijn Eetmeter” (My Eat-meter), a Dutch tool of the Netherlands Nutrition Centre that enables individuals to report their daily dietary intake [220]. Complementing the self-reported measurements with objective sales data is also recommended. This information can be combined with
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