Improving teens’ healthy snacking habits

This study aims to increase teens’ healthy snacking (fruits and vegetables) through a 2(motivation/no motivation)x2(ability/no ability) real-life intervention among teens between 12 and 15 years old. The research uses smartphones to set out questionnaires and the intervention itself. Motivation is being established by the use of self-persuasion, where participants have to come up with arguments to eat healthy aiming to increase intrinsic motivation. Ability is being established by the use of implementation intentions. This requires participants to specify plans on where and what they are going to eat. Healthy snack intention, actual snacking behavior, motivation and ability are all measured before and after intervention and with a delay of a couple of weeks to examine long-term effects.

We assume that:

- Compared to teens in the control condition, those who receive the self-persuasion intervention (motivation condition) will develop more intrinsic motivation, which results in more healthy snacking.

- Compared to teens in the control condition, those who received the implementation-intention intervention (ability condition) will develop more ability to snack healthy, which results in more healthy snacking.

- Teens who received both the self-persuasion & implementation intention intervention (the motivation & ability condition) will eat more healthy than teens in the motivation condition, or than teens in the ability condition, or than teens in the control condition.

baseline and intervention October 2016, follow-up December 2016

Participants receive a smartphone for 10 days through which they can only access a research app. The first days are used to gather baseline information through questionnaires, the intervention starts at the middle of the week. Teens in the motivation condition are asked to type in two reasons why it is important to eat healthy (self-persuasion technique). Teens in the ability condition are asked to establish an if-then statement by answering questions on when they snack unhealthy and which healthy snack they prefer (implementation-intention technique). This results in a personalized if-then statement, which they are asked to say aloud three times. Teens in the motivation- and ability condition will receive both tasks, and teens in the control condition will receive a non-related task (homework task). Follow-up will be conducted after a couple of weeks.