Mind the gap: Habit and self‐determined motivation predict health behaviours in middle‐aged and older adults

OBJECTIVES Physical activity and fruit and vegetable consumption are two key health behaviours associated with the health and well-being of middle-aged and older adults. The present research investigated how habit and self-determined motivation interact with intention to prospectively predict physical activity and fruit and vegetable consumption in middle-aged and older adults. DESIGN A prospective correlational design (two data collection points) was used. METHODS A convenience sample of 195 adults completed online questionnaires measuring intention, habit, and self-determined motivation. One week later, 177 participants (67.2% female), aged 52-87 years (M = 61.50, SD = 5.90), completed self-report measures of physical activity and fruit and vegetable consumption over the previous week. RESULTS Separate hierarchical multiple regression analyses were conducted. For physical activity, the model explained 46% of the variance in behaviour, F(8, 168) = 17.88, p < .001 and a large effect size (ƒ2  = .85). Two-way interactions contributed an additional 3.70% of unique variance in physical activity, F(3, 165) = 4.07, p = .008, ƒ2  = .04. For fruit and vegetable consumption, the model explained 19.20% of the variance in behaviour, F(5, 171) = 8.13, p < .001 and a medium effect size (ƒ2  = .24). Two-way interactions did not significantly improve the model, F(3, 168) = 1.68, p = .174. CONCLUSIONS Habit and self-determined motivation were both important in narrowing the intention-behaviour gap for two key health behaviours, and combining these processes may better inform strategies to support people's intentions to improve these health behaviours.