The present study aimed to explore the mediating role of family-related determinants on the effects of the ToyBox-intervention on pre-school children’s consumption of healthy and unhealthy snacks.

The ToyBox-intervention was a kindergarten-based, family-involved intervention with a cluster-randomized design, aiming to promote healthy lifestyle behaviours to prevent obesity at pre-school age.

Kindergartens (n 309) in six European countries.

A total of 6290 pre-schoolers and their families participated in the ToyBox-intervention in 2012–2013 and data from 5212 pre-schoolers/families were included in the current analyses.

Even though the total effect of the ToyBox-intervention on healthy and unhealthy snacking was not significant, the ToyBox-intervention significantly improved parental rule setting on children’s unhealthy snack consumption (i.e. restriction of snacking while watching television and permission only at certain occasions) and parental consumption of unhealthy snacks, while it increased parental knowledge on snacking recommendations. Regarding healthy snacking, the ToyBox-intervention improved children’s attitude towards fruit and vegetables (F&V). All previously mentioned family-related determinants mediated the intervention effects on pre-schoolers’ consumption of healthy and unhealthy snacks. Almost all family-related determinants examined in the study were independently associated with pre-schoolers’ consumption of healthy and unhealthy snacks.

The intervention was effective in improving relevant family-related determinants. Interventions aiming to promote F&V consumption and limit the consumption of unhealthy snacks in pre-schoolers should target on these mediators, but also identify new family-, school- or peer-related determinants, to enhance their effectiveness.

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.