Running head: ONE-HOUR ONLINE INTERVENTION ON FRUIT INTAKE 1 Self-Regulation Prompts Can Increase Fruit Consumption: A One-Hour Randomized Controlled Online Trial

Objective: The purpose was to examine whether a one-hour intervention would help increase fruit consumption in motivated individuals and to study the role of self-regulatory mechanisms in the behavior change process, with a particular focus on dietary planning and action control. Methods: A randomized controlled trial compared a one-hour online intervention with controls in 791 participants. Dependent variables were fruit intake, planning to consume, and dietary action control. Results: Experimental condition by time interactions documented superior treatment effects for the self-regulation group, although all participants benefited from the study. To identify the contribution of the intervention ingredients, multiple mediation analyses were conducted that yielded mediator effects for dietary action control and planning. Conclusions: A very brief self-regulatory nutrition intervention was superior to a control condition. Dietary planning and action control seem to play a major role in the mechanisms that facilitate fruit intake.