We conducted a cluster randomised controlled trial of parents in 56 primary schools and community service centres (clusters) to evaluate the effectiveness of a single-session workshop on promoting more fruit and vegetable (FV) intake. A total of 803 parents were randomised to the FV intervention arm (16 clusters, n = 197), the more appreciation control arm (19 clusters, n = 270), or the less criticism control arm (21 clusters, n = 336). The FV intake of the FV arm was compared with that of the combined more appreciation or less criticism (MALC) arm. Both arms received a 2 h workshop: (i) the FV arm on increasing FV consumption and related food literacy; (ii) the MALC arm on increasing appreciation or reducing criticism of children. Primary outcomes were FV consumption per day in the past week assessed at baseline, 2-weeks, and 6-weeks. Secondary outcomes were behavioural determinants proposed by the Health Action Process Approach (HAPA), including outcome expectancies, self-efficacy, intention, and planning behaviour. The FV arm had a greater increase in FV consumption than the MALC arm, with large effect sizes (d: 0.97-1.08) and improvements in behavioural determinants with small effect sizes at all time points (d: 0.19-0.43). Our study was the first population-based randomised controlled trial to show that a brief, single 2 h HAPA-based workshop was effective in promoting fruit and vegetable intake in parents.
Keywords: behaviour change; dietary intakes; fruit and vegetable; primary prevention; randomised controlled trial.