Improving adult eating behaviours by manipulating time perspective: a systematic review and meta-analysis

There is a growing body of research on improving health behaviours through future thinking but that in improving eating behaviour remains unclear. Hence, we conducted a systematic review and meta-analysis on the effectiveness of time perspective manipulation in improving adult eating behaviours. Articles published from inception through 17 March 2022 were retrieved from eight databases (CINAHL, Embase, ProQuest, PsycINFO, PubMed, Scopus, The Cochrane library, and Web of Science). Meta-analysis was conducted using random effects models with effect sizes reported in Hedges' g. Sixteen experimental studies were included, representing 1,914 participants with mean ages ranging from 20.5 to 44.1 years old and mean baseline BMI of 22.0 kg/m² to 37.2 kg/m². The interventions included were episodic future thinking (EFT; n = 12), message framing (n = 2), and varying inter-meal intervals (IMI; n = 2) in improving food choices, food intake and portion size. Two studies reported significant interventional effectiveness for domain-specific EFT while all studies on message framing and IMI reported significant interventional effectiveness. Message framing seemed to be more effective when both temporal distance and valence frames were manipulated. However, the pooled effect sizes of all the interventions did not result in a significant interventional effect (n = 5; g = -0.49; 95% confidence interval (CI) = -1.44, 0.47; p = 0.23; I²=87.2%). More rigorous research is needed to ascertain the effectiveness of manipulating time perspective in improving eating behaviours before such interventions are more widely used.