Adolescents’ snacking habits are driven by both explicit reflective and implicit hedonic processes. Hedonic pathways and differences in sensitivity to food rewards in addition to reflective determinants should be considered. The present study evaluated the feasibility and impact of a mobile phone-delivered intervention, incorporating explicit reflective and implicit rewarding strategies, on adolescents’ snack intake.

Adolescents (n 988; mean age 14·9 (sd 0·70) years, 59·4 % boys) completed a non-randomized clustered controlled trial. Adolescents (n 416) in the intervention schools (n 3) were provided with the intervention application for four weeks, while adolescents (n 572) in the control schools (n 3) followed the regular curriculum. Outcomes were differences in healthy snacking ratio and key determinants (awareness, intention, attitude, self-efficacy, habits and knowledge). Process evaluation data were collected via questionnaires and through log data of the app.

No significant positive intervention effects on the healthy snack ratio (b=−3·52 (se 1·82), P>0·05) or targeted determinants were observed. Only 268 adolescents started using the app, of whom only fifty-five (20·5 %) still logged in after four weeks. Within the group of users, higher exposure to the app was not significantly associated with positive intervention effects. App satisfaction ratings were low in both high and low user groups. Moderation analyses revealed small positive intervention effects on the healthy snack ratio in high compared with low reward-sensitive boys (b=1·38 (se 0·59), P<0·05).

The intervention was not able to improve adolescents’ snack choices, due to low reach and exposure. Future interventions should consider multicomponent interventions, teacher engagement, exhaustive participatory app content development and tailoring.

To study diet quality among pre-schoolers using the Diet Quality Index (DQI) and to investigate differences according to gender, socio-economic status (SES) and overweight/obesity status.

Kindergarten-based cross-sectional survey within the ToyBox-study. A standardized protocol was used and parents/caregivers self-reported sociodemographic data and a semi-quantitative FFQ. A total DQI and its four subcomponents (diversity, quality, equilibrium and meal index) were calculated based on this FFQ. High total DQI scores indicate better diet quality than low scores. Results of the total DQI and the subcomponents were reported as percentages of maximum scores (100 %).

Kindergartens in six European countries (Belgium, Bulgaria, Germany, Greece, Poland and Spain).

European pre-schoolers (aged 3·5–5·5 years) and their parents/caregivers (n 7063).

The mean total DQI score was 68·3 %. Mean scores of the subcomponents were 61·7 % for diversity, 56·5 % for quality, 65·4 % for equilibrium and 89·7 % for the meal index. Pre-schoolers of lower-SES backgrounds had lower scores on the total DQI and all its subcomponents. No clear differences were found by gender and overweight status. Results differed slightly according to country.

Pre-schoolers scored low on the total DQI and especially on dietary quality, as energy-dense, low-nutritious food items were more often consumed than highly nutritious food items. Furthermore, already in pre-schoolers lower-SES mothers were less likely to provide a good diet quality and this was consistent for all four subcomponents of the total DQI. Food intake in pre-schoolers should be enhanced, especially in pre-schoolers of lower-SES backgrounds.

The present study aimed to examine the impact of non-wear activities registered in diaries when using accelerometers to assess physical activity (PA) in young adolescents.

Data arise from a large-scale cross-sectional study on PA. PA was objectively assessed using Actigraph™ accelerometers (Actigraph MTI, Manufacturing Technology Inc., Pensacola, FL, USA) during seven consecutive days. Non-wear time activity diaries were provided to register the activities for which the accelerometer was removed. After correction to deal with over-reporting, the registered minutes of PA were used to replace periods of non-wear time measured by the accelerometer.

Between October 2008 and May 2009 adolescents were recruited by home visits in Ghent (Belgium).

Young adolescents (n 513; 48·6 % boys) aged 13 to 15 years.

Of the total sample, 49·9 % registered at least one activity of moderate to vigorous intensity in the non-wear time activity diary. More adolescents registered an activity performed on a weekday than on a weekend day and the registered mean number of minutes of moderate to vigorous PA were higher on weekend days. Repeated-measures (M)ANOVA tests revealed a significant difference between the mean minutes with and without non-wear activities for all PA intensities, regardless of adolescents’ socio-economic status or gender. More adolescents achieved the PA recommendations after inclusion of the non-wear activities irrespective of accelerometer thresholds used.

The collection of information regarding non-wear time by non-wear time activity diaries when using accelerometers in 13–15-year-old adolescents can lead to different PA outcomes at the individual level and therefore can improve the ability to accurately measure PA.

To evaluate the effects of a middle-school healthy eating promotion intervention combining environmental changes and computer-tailored feedback, with and without an explicit parent involvement component.

Clustered randomised controlled trial.

Fifteen West-Flemish (Belgian) middle schools.

A random sample of 15 schools with 2991 pupils in 7th and 8th grades was randomly assigned to an intervention group with parental support (n = 5), an intervention group without parental support (n = 5) and a control group (n = 5). In these 15 schools an intervention combining environmental changes with computer-tailored feedback was implemented. Fat and fruit intake, water and soft drinks consumption were measured with food-frequency questionnaires in the total sample of children.

In girls, fat intake and percentage of energy from fat decreased significantly more in the intervention group with parental support, compared with the intervention alone group (all F>3.9, P < 0.05) and the control group (all F>16.7, P < 0.001). In boys, there were no significant decreases in fat intake (F = 1.4, not significant (NS)) or percentage of energy from fat (F = 0.7, NS) as a result of the intervention. No intervention effects were found in boys or in girls for fruit (F = 0.5, NS), soft drinks (F = 2.6, NS) and water consumption (F = 0.3, NS).

Combining physical and social environmental changes with computer-tailored feedback in girls and their parents can induce lower fat intake in middle-school girls. However, to have an impact on the consumption of soft drinks and water, governmental laws that restrict the at-school availability of low-nutritive products may be necessary.

To investigate differences in reported physical activity levels and in perceived environmental and psychosocial correlates of activity between Portuguese and Belgian adults; and to analyse the relative contribution of environmental and psychosocial variables in explaining physical activity within different contexts in Portugal and Belgium.

Cross-sectional study.

One city in Portugal (Oeiras) and one in Belgium (Ghent).

In total 526 participants, 247 from Portugal and 279 from Belgium, completed the long International Physical Activity Questionnaire and a validated questionnaire on environmental and psychosocial correlates.

For the sum of all activities of at least moderate intensity, a significantly higher mean level of activity was found in Belgian adults (P < 0.001). However, comparable percentages of the Belgian (38%) and Portuguese (42%) samples did not meet the recommendation of 30 min per day. The variance explained by environmental factors was lower (1% to 8%) than by psychosocial factors (maximum 42%). Regression analyses showed activity-specific relations with environmental variables which were analogous in both countries. Walking/cycling for transportation and walking for recreation were related to social support from family and/or friends and to walkability and walking facilities in the neighbourhood. Recreational physical activity was mainly determined by social support, self-efficacy, and perceived benefits and barriers.

Activity campaigns addressing psychosocial determinants are needed to encourage leisure-time activity, while a combination of neighbourhood design changes and encouragement of social support in walking is warranted to increase walking in different contexts.