A systematic review and meta-analysis of applications of the self-report habit index to nutrition and physical activity behaviours

Background: Health behaviour models typically neglect habitual action. The Self-Report Habit Index (SRHI) permits synthesis of evidence of the influence of habit on behaviour. Purpose: The purpose of this study is to review evidence around mean habit strength, habit-behaviour correlations, and habit × intention interactions, from applications of the SRHI to dietary, physical activity, and active travel behaviour. Method: Electronic database searches identified 126 potentially relevant papers. Twenty-two papers (21 datasets) passed eligibility screening. Mean scores and correlations were meta-analysed using fixed, random and mixed effects, and interactions were synthesised via narrative review. Results: Twenty-three habit-behaviour correlations and nine habit × intention interaction tests were found. Typical habit strength was located around the SRHI midpoint. Weighted habit-behaviour effects were medium-to-strong (fixed: r = 0.44; random: r = 0.46). Eight tests found that habit moderated the intention-behaviour relation. Conclusion: More comprehensive understanding of nutrition and activity behaviours will be achieved by accounting for habitual responses to contextual cues.