Immediate effects of a very brief planning intervention on fruit and vegetable consumption: A randomized controlled trial.


Domke A(1), Keller J(1), Heuse S(2), Wiedemann AU(1)(3), Lorbeer N(1), Knoll N(1).
Author information:
(1)Department of Education and Psychology, Division Health Psychology, Freie Universität Berlin, Berlin, Germany.
(2)Department of Psychology, University of Applied Sciences Europe, Berlin, Germany.
(3)DearEmployee GmbH, Berlin, Germany.


Action planning interventions can effectively promote fruit and vegetable (FV) consumption, but not much is known about the day-to-day translation of intervention planning into action. In this randomized controlled trial, immediate intervention effects of a very brief planning intervention on FV consumption during the following 13 days were investigated. After a 13-day pre-intervention diary, N = 206 participants (aged 19-66 years) were randomly allocated to a waiting-list control condition or a planning condition, where they formed one FV plan. Participants from both conditions completed a 13-day post-intervention diary. Self-reported daily FV consumption, FV-specific self-efficacy, and action control were assessed. Segmented linear mixed models estimating a discrete change (i.e. "jump") between diary phases showed a positive "jump" of FV intake and self-efficacy in the planning condition when compared to the control condition. For action control, such effects were not observed. Changes in study variables throughout the post-intervention phase did not differ between both conditions. Present findings extend previous evidence on action planning interventions by showing that increases in self-regulatory (i.e. self-efficacy) and behavioral (i.e. FV intake) outcomes can occur very rapidly and already on the first day for which behavioral increases were planned.