Psychosocial determinants of fruit and vegetable intake in adult population: a systematic review

Abstract

BackgroundAccumulating evidence suggests that fruit and vegetable intake (FVI) plays a protective role against major diseases. Despite this protective role and the obesity pandemic context, populations in Western countries usually eat far less than five servings of fruits and vegetables per day. In order to increase the efficiency of interventions, they should be tailored to the most important determinants or mediators of FVI. The objective was to systematically review social cognitive theory-based studies of FVI and to identify its main psychosocial determinants.MethodsPublished papers were systematically sought using Current Contents (2007-2009) and Medline, Embase, PsycINFO, Proquest and Thesis, as well as Cinhal (1980-2009). Additional studies were identified by a manual search in the bibliographies. Search terms included fruit, vegetable, behaviour, intention, as well as names of specific theories. Only studies predicting FVI or intention to eat fruits and vegetables in the general population and using a social cognitive theory were included. Independent extraction of information was carried out by two persons using predefined data fields, including study quality criteria.ResultsA total of 23 studies were identified and included, 15 studying only the determinants of FVI, seven studying the determinants of FVI and intention and one studying only the determinants of intention. All pooled analyses were based on random-effects models. The random-effect R2 observed for the prediction of FVI was 0.23 and it was 0.34 for the prediction of intention. Multicomponent theoretical frameworks and the theory of planned behaviour (TPB) were most often used. A number of methodological moderators influenced the efficacy of prediction of FVI. The most consistent variables predicting behaviour were habit, motivation and goals, beliefs about capabilities, knowledge and taste; those explaining intention were beliefs about capabilities, beliefs about consequences and perceived social influences.ConclusionsOur results suggest that the TPB and social cognitive theory (SCT) are the preferable social cognitive theories to predict behaviour and TPB to explain intention. Efficacy of prediction was nonetheless negatively affected by methodological factors such as the study design and the quality of psychosocial and behavioural measures.

Promoting fruit and vegetable consumption. Testing an intervention based on the theory of planned behaviour

“…However, the model performed less well when used to predict behaviour. This is inconsistent with the findings from previous studies using the TPB to explain fruit and vegetable consumption (Guillaumie, et al, 2010), where the TPB has been found to predict behaviour as well as it predicts intention. The large gap between the predictive utility of the model when applied to behaviour rather than intention is more consistent with general reviews of the TPB which have found similar reductions in the predictive utility of the model when applied to behaviour (Armitage & Conner, 2001;Godin & Kok, 1996).…”

“…Results indicate that the model can be successfully applied to cross-sectional prediction of behaviour. This is consistent with reviews of the TPB across a range of behaviours (Armitage & Conner, 2001;Godin & Kok, 1996) and with previous studies which have applied the model to the prediction of fruit and vegetable intake in other populations (Guillaumie, et al, 2010). Interestingly the model was more effective at predicting behaviour at post-intervention.…”

“…This may reflect an increase in temporal stability and a more coherent understanding of fruit and vegetable consumption at post-intervention (Hardeman, Kinmonth, Michie, & Sutton, 2011). The predictive utility of the model when applied to intention to eat fruit and vegetables compared favourably with previous studies of the TPB as applied to fruit and vegetable consumption (Guillaumie, et al, 2010). These findings are also broadly consistent with recent studies which have applied the TPB to the prediction of other eating behaviours in Australian young adults.…”

“…Fresh Facts intervention materials designed to use this technique provided a number of suggestions for preparatory behaviour, such as carrying fruit and vegetables. These techniques may have led to increases in habitual performance of behaviour, a factor which would not be captured by measures designed to assess change in TPB variables, but which would be expected to lead to increased fruit and vegetable consumption (Guillaumie, et al, 2010;Shaikh, Yaroch, Nebeling, Yeh, & Resnicow, 2008).…”

“…In the context of fruit and vegetable intake, the model has been reported to account for an average of 41% of the variance in intention and 45% of the variance in behaviour (Guillaumie, Godin, & Vézina-Im, 2010). In their meta-analytic review of psychosocial predictors of fruit and vegetable intake, Guillaumie, Godin, and Vézina-Im argued that the TPB is the most strongly supported model of intention and behaviour (Guillaumie, et al, 2010), and therefore there is sound justification for the use of the model in interventions designed to increase intake of fruit and vegetables (Guillaumie, et al, 2010). …”