Understanding, promoting and predicting sustainable diets: A systematic review

The understanding of consumers' behaviours is crucial for developing strategies and educational interventions necessary to transition towards more sustainable diets at the individual and population level. In this regard, social-psychological models can be effective in identifying and understanding the role of the cognitive constructs behind the consumers’ behaviour. The present systematic review is aimed at identifying the main drivers and barriers towards the adoption of sustainable dietary behaviours in adult populations. Sixty-seven papers were analysed by applying at least one of the following three theoretical approaches: the Theory of Reasoned Action, the Theory of Planned Behaviour, and the Social Cognitive Theory. Most of the studies were conducted in industrialised countries and, with one exception, only one among health, environmental, socio-economic and qualitative dietary dimensions was considered in each study. The adoption (or the intention to adopt) a healthy or a low-fat diet was the most analysed. A multitude of significant predictors of intention and behaviour was found. The most recurrent predictors were attitude for intention and intention for behaviour. Social-psychological models can be relevant when applied to dietary behaviour contexts, but present limits in explaining behaviour when prospective and more objective tools to assess food consumption (e.g., food diaries and/or food frequency questionnaires) are used. By identifying the drivers of consumers’ behavioural changes, the collected results may support policy makers in providing recommendations and defining primary prevention interventions which enhance consumer awareness and engagement towards more sustainable dietary habits. •A systematic review on determinants of sustainable dietary behaviours is provided.•Attitude and intention are the most recurrent significant behavioural predictors.•Non-cognitive factors help the understanding of sustainable dietary behaviours.•Objective and prospective evaluation of behaviour tends to limit models' efficacy.•Results may help in defining recommendations and primary prevention interventions.