The World Health Organization estimates that 35 million children in developing countries and 8 million in developed countries have overweight or obesity, although in relative terms the percentages are higher in developed countries.1 Childhood obesity requires an interdisciplinary approach addressing the current eating habits and physical activity of our youth.

It has been demonstrated that in children and adolescents physical activity reduces blood cholesterol and lipid levels, hypertension, the risk of metabolic syndrome, overweight and obesity, injuries and symptoms of depression,2 and also improves different aspects of mental and social health.3 Unfortunately, the level of physical activity in children and adolescents has declined in recent years.4 Meanwhile, a healthy diet has been associated with an increased probability of being active and a decreased probability of sedentary behaviour and obesity.5

While many efforts have been made to improve the eating habits and increase the level of physical activity of the younger population, the impact of these efforts on their body composition is not clear.6 As a result, new intervention models have been developed with the purpose of providing healthy environments.7 In the case of children and adolescents, the school, which has a continuous and intensive contact with them, plays a key role in the environment where they develop, and thus should promote healthy habits.8 The World Health Organization is aware of this fact, and has established a series of recommendations, chief of which are: developing academic curricula that promote physical activity and a healthy diet, managing the food service environments, improving facilities and access to these facilities to promote physical activity, and providing in-service training for school staff.9 In Spain, the SESPAS report,10 which is aimed at the prevention of obesity, also emphasises the importance of intervening in the school setting.

Research on these new models of intervention based on healthy environments has increased significantly, especially in recent years11; however, these studies usually focus on neighbourhood environments as opposed to school settings. Therefore, the aim of our study was to analyse the eating habits and levels of physical activity of schoolchildren. Our secondary goal was to analyse the levels of physical activity of schoolchildren based on their sex.

Tables 1 and 2 summarise the most relevant results of the questionnaires completed by school administrators. Most schools partook in nutrition and/or physical activity programmes, although only some of them had had their staff specifically trained in these areas (16.1% and 38.7%, respectively). Health-promotion policies were not usually reflected in the school's educational goals, and less than half of the schools offered some type of organised physical activity during recess (48.4%) or lunch break (22.6%). In this regard, the improvement of outdoor spaces and equipment (which nearly 80% considered important or very important), and the involvement of families and students (with values approximating 90%) were the most highly rated aspects in relation to increasing physical activity.

Table 3 shows the main characteristics of the schoolchildren sample by sex, with particular emphasis on issues related to their activity habits. Boys reported significantly higher levels of activity than girls for every item pertaining to physical activity (P<.05), except during lunch break and between 6 and 10 pm. In addition, we did not find any significant differences between sexes in the daily hours of screen time.

The associations between individual and environmental variables are summarised in Table 4. This table only presents data for the aspects of school health promotion that had an impact on one or more health indicators in participants. Thus, schoolchildren whose teachers had received training on nutrition in recent years showed higher levels of physical activity (P=.010), a greater degree of compliance with the Mediterranean diet (P=.020) and fewer daily hours of screen time (P=.016) compared to peers whose teachers had not received such training. Meanwhile, schoolchildren attending schools with written or unwritten policies aiming at increasing the consumption of fruits and vegetables reported a higher compliance with Mediterranean dietary patterns (P=.017) and fewer hours of screen time per day (P=.023). Lastly, when it came to the physical environment, it is worth noting that students whose schools had sports facilities within the school grounds or in the vicinity showed higher levels of physical activity than students that did not have access to such facilities (P=.023).

The results showed that while few schools are members of the Schools for Health in Europe network (SHE network), most were implementing projects related to nutrition and physical activity. However, despite the fact that one of the keys to the success of such programmes is training the individuals that carry them out,18 we observed that teachers were given specific training in fewer than half of the schools. According to a study conducted on teachers that participated in these programmes, another key factor for success is that they be embedded in the educational goals or the mission of the school.19 However, most of the time the interventions to reduce consumption of unhealthy foods or increase healthy habits in the analysed schools stemmed from policies that were not specified in the school's educational goals. These trends were similar to those found in previous studies conducted in Spain20 and in the Health Behaviour in School-aged Children study, which was conducted in 364 schools throughout Spain in 2006.21

More than half of the schools organised physical or sports activities in the evening after school hours, but this percentage dropped significantly for recess and lunch breaks. When asked about the factors that influence physical activity in students, school administrators underscored the involvement of parents and students and the improvement of facilities, equipment and activities. In terms of parental and student involvement, a recent health promotion project implemented in 12 schools in the north east of Spain achieved positive results by formulating their strategies based on the opinions of parents and schoolchildren through committees that met regularly.22 As for the second factor, previous studies have found higher levels of physical activity in schools that had facilities, policies, and opportunities available for the improvement of these levels. Thus, boys that attended schools that scored high on these areas engaged in physical activity during school hours 53% more than their peers in lower-scoring schools, while in the case of girls the percentage of physical activity during spare time rose to 62%.23

As for the levels of physical activity, we observed higher values in boys, consistent with previous evidence for schoolchildren of similar ages (P<.001).24 The differences between the sexes were particularly marked for the overall weekly activity and for activity at specific times of day, such as recess. While some authors advocate the promotion of physical activity during recess,25 these differences had been observed in the past, with a larger percentage of boys engaging in vigorous physical activity and a lower percentage engaging in sedentary activities (P<.001 in both cases).26 However, previous studies have described similar benefits for both sexes, despite the lower levels of activity reported by girls,27 which may suggest the need to adjust physical activity recommendations based on sex.

While recent studies have associated neighbourhood features (access to parks, presence of fast food restaurants…) with the body composition of its inhabitants,28,29 the literature is not consistent when it comes to the effects of the school environment, although there is evidence that it influences the habits of students.6 In this regard, previous studies show that interventions that combined educational and environmental elements were more effective.30 This fact was demonstrated in a nationwide study conducted in Spain in which the physical activity of schoolchildren was directly correlated to the promotion policies of the schools they attended, so that 47.4% of students in schools with high levels of promotion met the recommendations for physical activity, while only 33.1% of students did in schools with low health promotion levels.31

In our study, students whose schools had multi-sport game courts reported higher levels of physical activity than students who did not have access to such facilities. The association between conducive environments and the practise of physical activity have been studied in the past. Access to playgrounds after school hours was associated with the total amount of physical activity in adolescents in the United States (P=.016).32 Similarly, moderate or vigorous physical activity was also influenced by the school physical environment in Canadian children (P<.005).33 However, none of these studies found an association with body composition, which is consistent with a recent review that did not find conclusive results concerning the availability/adequacy of the multi-sport game courts and the body mass index of the schoolchildren.34

Last of all, students whose teachers had received training on nutrition not only scored higher on their compliance with the Mediterranean diet, but showed higher levels of physical activity and fewer hours of screen time per day. This may be explained by the observed association between sedentary behaviours, physical activity and eating habits.5 Likewise, schoolchildren whose schools had written or unwritten policies regarding the consumption of fruits and vegetables also reported fewer hours of screen time per day and a greater compliance with the Mediterranean diet, which demonstrates the influence of the coordination of school staff. The education and recommendations that students receive about their diet are significant insofar as the food service environment was associated with the body composition of the schoolchildren.35

The results we obtained emphasise the importance of schools on lifestyle habits and the prevention of overweight and obesity, and thus on the future health of our young.

Most of the schools had health-promoting programmes, although there was room for improvement, for instance in staff training or the promotion of physical activity during school hours. In spite of this, some elements like the training and coordination of the teaching staff or the availability of multi-sport courts were positively correlated with the physical activity and eating habits of the students, thus influencing their health. Considering the age of the schoolchildren and the continued and intensive contact they have with their school, the latter affords an optimal setting for health promotion. Therefore, the school and health authorities should work in close collaboration to facilitate the creation of healthy environments in schools.

This study was funded partially by the Institute of Studies of the Government of La Rioja.

The authors have no conflicts of interest to declare.