Prediction of fruit and vegetable intake: The importance of contextualizing motivation.

OBJECTIVES
Motivation is identified as a key antecedent of self-regulated behaviour, such as eating fruit and vegetables. However, inaccurate measurement of this construct may lead to poor prediction of behaviour and inflate the impact of post-motivational factors, such as planning, in models of health behaviour. This study explored the properties of a newly identified measure of motivation, termed behavioural resolve (Rhodes & Horne, 2013, Psychol. Sport Exerc., 14, 455-460), in relation to intention, planning, and fruit and vegetable intake (FVI).

DESIGN
Prospective self-report survey.

METHOD
University students living in the United Kingdom completed two online surveys. The first assessed demographic and predictor variables (intention, behavioural resolve, action planning, and coping planning). The second, completed approximately 2 weeks later, measured average daily FVI and perceived experience of obstacles to FVI. At Time 1, there were 195 respondents, with 139 providing follow-up data.

RESULTS
All predictor variables were significantly correlated with FVI. Two independent multiple hierarchical regression analyses revealed that both intention and behavioural resolve were significant predictors of FVI, but behavioural resolve explained greater FVI variance (40.1%) than intention (36.4%). Furthermore, action planning showed incremental predictive utility over intention, but not behavioural resolve, in predicting FVI.

CONCLUSIONS
The results indicated that motivation is an important determinant of FVI for students, with behavioural resolve demonstrating advantages over intention as a measure of this domain and a predictor of FVI behaviour. Statement of contribution What is already known on this subject? Many of those who intend to increase their fruit and vegetable intake (FVI) do not succeed. The contribution of planning to theoretical models predicting FVI may be the result of inadequate assessment of motivation. Research is needed to establish accurate measures of the determinants of FVI and create interventions to increase suboptimal intake in student populations. What does this study add? This study is the first to demonstrate the additive effects of behavioural resolve upon intention in predicting FVI for UK students. Volitional planning made no contribution.